Evaluate (8x^2+8x)-(-9x^2+8x)

$(8 x^{2} + 8 x) - (- 9 x^{2} + 8 x)$

Simplify each term.

Apply the distributive property.

$8 x^{2} + 8 x - (- 9 x^{2}) - (8 x)$

Multiply $- 9$ by $- 1$ .

$8 x^{2} + 8 x + 9 x^{2} - (8 x)$

Multiply $8$ by $- 1$ .

$8 x^{2} + 8 x + 9 x^{2} - 8 x$

Simplify by adding terms.

Combine the opposite terms in $8 x^{2} + 8 x + 9 x^{2} - 8 x$ .

Subtract $8 x$ from $8 x$ .

$8 x^{2} + 9 x^{2} + 0$

Add $8 x^{2} + 9 x^{2}$ and $0$ .

$8 x^{2} + 9 x^{2}$

Add $8 x^{2}$ and $9 x^{2}$ .

$17 x^{2}$