Simplify 3z-7z^2-5z+5z^2+2z^2

$3 z - 7 z^{2} - 5 z + 5 z^{2} + 2 z^{2}$

Subtract $5 z$ from $3 z$ .

$- 7 z^{2} - 2 z + 5 z^{2} + 2 z^{2}$

Add $- 7 z^{2}$ and $5 z^{2}$ .

$- 2 z^{2} - 2 z + 2 z^{2}$

Combine the opposite terms in $- 2 z^{2} - 2 z + 2 z^{2}$ .

Add $- 2 z^{2}$ and $2 z^{2}$ .

$- 2 z + 0$

Add $- 2 z$ and $0$ .

$- 2 z$