Simplify (10x^2-10x-6)+(x+6)

$(10 x^{2} - 10 x - 6) + (x + 6)$

Remove parentheses.

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

Combine the opposite terms in $10 x^{2} - 10 x - 6 + x + 6$ .

Add $- 6$ and $6$ .

$10 x^{2} - 10 x + x + 0$

Add $10 x^{2} - 10 x + x$ and $0$ .

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

Add $- 10 x$ and $x$ .

$10 x^{2} - 9 x$