Solve for: (3x^2-5x+7)-(-2+6x-7x^2)

Expression: $\left( 3{x}^{2}-5x+7 \right)-\left( -2+6x-7{x}^{2} \right)$

Remove unnecessary parentheses

$3{x}^{2}-5x+7-\left( -2+6x-7{x}^{2} \right)$

When there is a $-$ in front of an expression in parentheses, change the sign of each term of the expression and remove the parentheses

$3{x}^{2}-5x+7+2-6x+7{x}^{2}$

Collect like terms

$10{x}^{2}-5x+7+2-6x$

Collect like terms

$10{x}^{2}-11x+7+2$

Add the numbers

$10{x}^{2}-11x+9$