**Answer:**

4+5=9

**Step-by-step explanation:**

a2+b=9

Two negatives equal a positive you multiply 2, 2 times because of the power 2.

**Answer:**

The equation that will determine the cost of two folders is; 3x = 2× $2.91

and the cost of the 2 folders is** $1.94**

**Step-by-step explanation:**

To solve this problem, we will follow the steps below;

Using proportion;

Let x be the cost of 2 folders

3 folders = $2.91

2 folders = x

Cross-multiply

3x = 2× $2.91

The equation that will determine the cost of two folders is

3x = 2× $2.91

We can go ahead and solve

3x = $5.82

Divide both-side of the equation by 3

=

x = $ 1.94

The cost of 2 folders is** $1.94**

**Answer: 18**

**Step-by-step explanation:**

subtract 5 - 7; since that's not possible make the 3 into a 2 and add a 1 in front of the 5; now do 15-7 = 8. 2-1 =1 ----> 18

You need to memorize how to factor cube roots, i.e. x^3 - y^3 or x^3 + y^3.

You left a + or - sign out but:

Here you have the difference of 2 cubes.

Then (3x - 4)( 9x^2 + 12x + 16)

or (3x+ 4)( 9x^2 - 12x + 16)