Question

subtract 9a³-7a²+5a+7 from -4a³+5a²-3a-2​

Answer 1

-4a3 +5a2-3a-2-9a3+7a2-5a-7
=-13a3+12a2-8a-9

Answer 2

$\left(-4a^3+5a^2-3a-2\right)-\left(9a^3-7a^2+5a+7\right)$

$=-4a^3+5a^2-3a-2-\left(9a^3-7a^2+5a+7\right)$

$=-4a^3+5a^2-3a-2-9a^3+7a^2-5a-7$

$=-13a^3+12a^2-8a-9$