Question

From the sum of 3a^2−ab−2b^2 and 2a^2+5ab−3b^2 subtract a^2−3ab−4b^2

Answer 1

$(3a^2-ab-2b^2) + (2a^2+5ab-3b^2) - (a^2-3ab-4b^2)$

First we distribute the negative throughout the last polynomial:

$(3a^2-ab-2b^2) + (2a^2+5ab-3b^2) + (-a^2+3ab+4b^2)$

Combine like terms:

$4a^2 + 7ab - b^2$