(5x + 6x3 + 2x) - (3x - 2x3 - 7x2) is equivalent to: 8x3 + 12x2 - X
B
4x3 -- 5x2 - x
C
-4x3 + x2 + 6x
2x3 + 4x2 -- 5x

A- 8x^3 + 12x^2 - x

Step-by-step explanation:

The symbol ^ with a 2 is squared and ^ with 3 means cubed.

1. Add a 1 before the parenthesis on both sides. Now, the equation should look like 1(5x^2 + 6x^3 + 2x) -1(3x - 2x^3 - 7x^2).

2. Now we should distribute. 1 × 5x^2 + 1 × 6x^3 + 1 × 2x -1 × 3x + -1 × -2x^3 + -1 × -7x^2.

3. Now the equation should be simplified.

1 × 5x^2 = 5x^2

1 × 6x^3 = 6x^3

1 × 2x = 2x

-1 × 3x = -3x

-1 × -2x^3 + -1 = 2x^3 -1. In this equation, there is a +- sign together, which is the same as a - sign.

-1 × -7x^2 = 7x^2

4. The new equation is 5x^2 + 6x^3 + 2x - 3x + 2x^3 - 1 + 7x^2

5. Now you can combine the like terms. 5x^2 and 7x^2 can be added, so 5x^2 + 7x^2 is equal to 12x^2. Also, 6x^3 and 2x^3 can be added, so 6x^3 + 2x^3 is equal to 8x^3. Lastly, 2x and -3x can be combined, so 2x - 3x is equal to -1x or -x.

6. So, the simplified equation is 12x^2 + 8x^3 -x. You can also write it as 8x^3 + 12x^2 - x. So, A is the answer.