Question

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

Answer 1

Answer:

Let q should be subtracted.

Then according to question,

3x2−4y2+5xy+20−q=−x2−y2+6xy+20

⇒q=3x2−4y2+5xy+20−(−x2−y2+6xy+20)

⇒q=3x2−4y2+5xy+20+x2+y2−6xy−20

⇒q=3x2+x2−4y2+y2+5xy−6xy+20−20

⇒q=4x2−3y2−xy+0

Hence, 4x2−3y2−xy should be subtracted.