Question

what should be taken away from 3x^2-4y^2+5xy+20 to obtain -x^2-y^2+6xy+20

Answer 1

Hii

Let the number substacted be a

Then

3x²-4y²+5xy+20-a= -x²-y²+6xy+20

3x²+x²-4y²+y²+5xy-6xy+20-20=a

4x²-3y²-xy=a

Then the number which should taken away is 4x²-3y²-xy