Solve (9a^2+8ab-7b^2)+(6a^2-5ab-4b^2)

$$( 9 a ^ { 2 } + 8 a b - 7 b ^ { 2 } ) + ( 6 a ^ { 2 } - 5 a b - 4 b ^ { 2 } )$$

Evaluate

$$15a^{2}+3ab-11b^{2}$$

Solution Steps

Combine 9a^{2} and 6a^{2} to get 15a^{2}.

$$15a^{2}+8ab-7b^{2}-5ab-4b^{2}$$

Combine 8ab and -5ab to get 3ab.

$$15a^{2}+3ab-7b^{2}-4b^{2}$$

Combine -7b^{2} and -4b^{2} to get -11b^{2}.

$$15a^{2}+3ab-11b^{2}$$

Differentiate w.r.t. a

$$3\left(10a+b\right)$$