Solve (7x^2-xy+y^2)+(-x^2-8xy+6y^2)

$$( 7 x ^ { 2 } - x y + y ^ { 2 } ) + ( - x ^ { 2 } - 8 x y + 6 y ^ { 2 } )$$

Evaluate

$$6x^{2}-9xy+7y^{2}$$

Solution Steps

Combine -xy and -8xy to get -9xy.

$$7x^{2}-9xy+y^{2}-x^{2}+6y^{2}$$

Combine y^{2} and 6y^{2} to get 7y^{2}.

$$7x^{2}-9xy+7y^{2}-x^{2}$$

Combine 7x^{2} and -x^{2} to get 6x^{2}.

$$6x^{2}-9xy+7y^{2}$$

Differentiate w.r.t. x

$$12x-9y$$