Jessica sold half of her comic books and then bought 9 more. She now has 13. How many did she begin with?
Step 1: Define your variable(s)
Step 2: Write an equation.
Step 3: Solve your equation.Step 5: Write a summary statement explaining your solution in the context of the problem..
Step 4: Check your solution.
Step 5: Write a summary statement explaining your solution in the context of the problem..
please helpp me .

Answer:

5

Step-by-step explanation:

To find the common difference you just find the difference between each number. 18-13=5,  23-18=5,  etc.

Answer: awnswer mine for 53 points

Step-by-step explanation:

Answer: 4 large bottles of water for $3.

Step-by-step explanation: To find how many large water bottles you can buy with $3, you’ll have to divide 12 by 3 which equals to 4. You can check your answer by multiplying 4 x 3 which equals to 12, which is the original amount of large water bottles you can buy for $9.

Answer:First suppose that the roots of the equation

x2−bx+c=0(1)

are real and positive. From the quadratic formula, we see that the roots of (1) are of the form

b±b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√2.

For the root or roots to be real, we require that b2−4c≥0, that is, b2≥4c. In order for them to be positive, we require that

b−b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√>0.

This immediately tells us that b>0, but we can go further. We can rearrange this to get

b>b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√,

which (assuming that b>0) is true if and only if

b2>b2−4c,

since both sides of the inequality are positive so we may square. But then

4c>0.

That is, if the roots are real and positive then b>0 and b2≥4c>0.

Now suppose that b>0 and b2≥4c>0.

Then the roots of (1) are real since b2−4c≥0, and b>0 guarantees that the root b+b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√ is positive.

So it remains to show that b−b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√>0. We have that

4c>0,

so that

b2>b2−4c,

then square rooting shows that

b>b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√,

so the roots of (1) are real and positive, as required.

Approach 2

the curve y equals x squared minus b x plus c showing two positive roots for y equals zero

This is intended to be a proof without words! We have from the diagram that:

If c, b and b2−4c are all positive, there are two real positive roots for x2−bx+c=0 (if b2=4c, we have two real positive equal roots).

If there are two real positive roots for x2−bx+c=0, then c and b are positive and b2−4c is non-negative.

(Why is the distance between the roots b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√?)

Approach 3

When solving problems about the roots of polynomials, it is often useful to find expressions those roots must satisfy and see if this tells us anything new. If α and β denote the roots of the equation, then

x2−bx+c=(x−α)(x−β)=x2−(α+β)x+αβ

and so α+β=b and αβ=c.

We also know that the roots of a quadratic equation are real if and only if the discriminant is non-negative, that is, if and only if b2−4c≥0.

Using these facts, if α and β are both real and positive, then b=α+β>0, c=αβ>0 and b2≥4c, as above.

Conversely, if b>0 and b2≥4c>0, then we know the discriminant is positive and hence both roots are real. We also have that

αβ>0(2)

and

α+β>0.(3)

As α and β are both real, by (2), we know that α and β are either both positive or both negative. However, if α and β were both negative, then (3) could not possibly hold. Hence α and β are both positive, as required.

We now sketch on a graph the region where b>0, c>0 and b2≥4c:

The curve b squared = 4 c as a quadratic with the c-axis vertical and the b-axis horizontal. The region below it is shaded.

The region of the b-c plane for which b>0, c>0 and b2≥4c

Sketch the region of the b-c plane in which the roots of the equation are real and less than 1 in magnitude.

We know that in order for the roots to be real we need b2≥4c as in the first part. We now need to find the region where

−1<b±b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√2<1.(4)

We have b−b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√2≤b+b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√2 so we only need to consider the values for which both

−1<b−b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√2andb+b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√2<1.

Firstly, we will consider the values for which

b+b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√<2.

Rearranging gives

b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√<2−b.

So b<2, as the square root is non-negative, and we can square both sides to get

b2−4c<4−4b+b2,

which we may rearrange to find c>b−1.

We will now consider the values for which

−2<b−b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√.

Similarly, we can rearrange to get

b2−4c⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯√<b+2.

So b>−2, and we can, as before, square to get

b2−4c<b2+4b+4,

and hence c>−b−1.

To sketch the graph, we start by considering the boundary curves b2=4c, c=b−1 and c=−b−1, and the points at which they intersect. We can see that the two lines only intersect when b=0 and c=−1, and the lines intersect the curve when

b2=4b−4andb2=−4b−4

which rearrange to

(b−2)2=0and(b+2)2=0.

This tells us that each line intersects with the curve in only one place and so these lines must be tangent.

Is there a way we could have deduced this directly from (4)?

What do the lines being tangent signify in terms of our equation x2−bx+c=0?

Is this a representation of a well-known property of these equations?

Sketching the graph then yields the following picture:

The graph with the previous curve and the lines 4 c = 4 b minus 4 and 4 c = minus 4 b - 4. Each line touches the curve once and the two lines intersect at (0, minus 1). The region between the three lines/curves is shaded.

The shaded region is where b2≥4c, c>b−1, c>−b−1 and −2<b<2

We might notice that when we derived the inequalities c>b−1 and c>−b−1, a lot of the work we did was very similar.

We might also notice that the graph above is symmetric about the c axis. Why is this?

Does the graph give us any ideas about how we might deduce one inequality from the other?

Step-by-step explanation:

The first option

Factoring [tex]6x^2+7x-10[/tex]

gives us:

[tex]\left(6x-5\right)\left(x+2\right)[/tex]

so we know that the first option,

one of the factors is (x+2) is correct.

Answer:

The one in the top left corner I THINK

Step-by-step explanation:

It is on baisically the same line and makes the most sense to ME.

DO NOT PICK ME IF YOU ARE NOT SURE!!!

Answer:

y=-4x+2

Step-by-step explanation:

B is the y-intercept and M is the sope, or x, knowing this now we slove:

(-4, 2)

m    b

y=mx+b

y=-4x+2

Have a beautiful day! v(⌒o⌒)v♪

For more help take a look at the picture below.

Answer:

1.she is not working and the iran.

Answer:

23

Step-by-step explanation:

15% of 20 = 3  then add the 3 to the 20 to get 23

23Answer:

Step-by-step explanation:

15/100*20 = 3

20+3 = 23

Answer:

Step-by-step explanation:

y=1/2x-3

Answer: x(x−6)

Step-by-step explanation:

Answer:

(x+0)(x-6) OR x(x-6)

Step-by-step explanation:

AC 1*0...AC=0

B -6...B=-6

AC 0*-6

B 0-6

(x+0)(x-6) OR x(x-6)

Answer:

0

Step-by-step explanation:

m= y2-y1/x2-x1

=0-0/-3-5

=0/-8

=0

Answer:

Slope = 0

Step-by-step explanation:

Answer:

It's 99. 7% 95% and 68% for std dev respectively

Give brainliest thanks

Answer: Option 2

Pls mark me brainilest!

Step-by-step explanation:

The Answer is:

−30xi−18x, I really don't know what you are looking for but this is what i came up with. Hope this is helpful!

Answer:

Elevator 2

Step-by-step explanation:

Well let's make this simply by focusing on elevator number 1

it is on the 6th floor so we represent that as

6

Now it goes up 7/4 which is also the same as 1 3/4

the equation looks like this:

6+1 3/4

Add them together:

7 3/4

Now it goes down 10 meaning it is -10 add that to the equation:

7 3/4 - 10

Which is -2 1/4

Elevator number 1 is at floor number -2 1/4

Now for Elevator number 2

It is on the 20th floor which will make the equation looks like this:

20

Now it goes down five floors three times which can be represented like this:

20-5(3)

Simplify (Multiplication goes first according to the Order of Operations)

20-15= 5

Now it is 5 but it goes up 12 floors so the equation looks like this:

5+12

Simplify:

17

Now you could tell that elevator 2 ends up on a higher floor

Hope this helps!

Answer:

18.75 feet

Step-by-step explanation:

Step 1

we find the length of Philip's rectangular deck in yards

The ratio of the width to the length is 4 to 5.

Philip's rectangular deck is 5 yards wide.

Hence,

Hence:

4/5 = 5/x

Cross Multiply

4x = 5 × 5

4x = 25

x = 25/4

x = 6.25 yards

The length of Philip's field = 6.25 yards

Hint: 1 yard = 3 feet.

Converting the yard to feet

1 yard = 3 feet

6.25 yards = x

Cross Multiply

x = 6.25 × 3 feet

x = 18.75 feet

Therefore, the length of Philip's field in feet = 18.75 feet

Answer:

y = -2/3x +3

Step-by-step explanation:

Answer:

3a-8

Step-by-step explanation:

(3a-4) -4

= 3a-4-4

= 3a-8

Answer: 125x125

Step-by-step explanation:

Answer: You can go online and type ps5 and it will get shipped to you. Or you can check Target, Bestbuy, Gamestop and etc.

Step-by-step explanation:

Answer:

gamestop or online!!

Step-by-step explanation:

hope this helps!!

Answer:

2^5

Step-by-step explanation:

Answer:

what is the question and where is it?

Step-by-step explanation:

Answer:

y<4

Step-by-step explanation:

thats your answer :)

Answer:

A

Step-by-step explanation:

Given a line with slope m then the slope of a line perpendicular to it is

[tex]m_{perpendicular}[/tex] = - [tex]\frac{1}{m}[/tex] = - [tex]\frac{1}{\frac{4}{5} }[/tex] = - [tex]\frac{5}{4}[/tex] → A

Answer:

Brand A: $0.40

Brand B:  $0.30

Brand C: $0.25

Brand D: $0.20

Answer:

Step-by-step explanation:

1. 0.40

2. 0.30

3. 0.25

4. 0.20

Answer:

5×(+1)=

5×1=5

Step-by-step explanation:

hope it helps

Answer:

Step-by-step explanation:

if you're going for distributive law then 5(-5)+5(6). -25+30. so 5