Simplify (-x^2+5x+2)+(6x^2+x)

$(- x^{2} + 5 x + 2) + (6 x^{2} + x)$

Remove parentheses.

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

Add $- x^{2}$ and $6 x^{2}$ .

$5 x^{2} + 5 x + 2 + x$

Add $5 x$ and $x$ .

$5 x^{2} + 6 x + 2$