Question

13) What must be added to (- 2x square+ óxy+7 ) to obtain ( 3x square - xy +1)? *​

Answer 1

Answer:

Let "a" be added to x^2 + xy +y^2 to obtain 2x^2 + 3xy

So a = 2x^2 + 3xy - (x^2 + xy + y^2) = 2x^2 + 3xy - x^2 - xy - y^2 = x^2 + 2xy - y^2.

So x^2 + 2xy - y^2 must be added.

Answer 2

5x² - 7xy - 6 should be added to -2x² + 6xy + 7 to obtain 3x² - xy + 1.

Let

• A = -2x² + 6xy + 7
• B = 3x² - xy + 1

Let m should be added to A to obtain B.

• m = 3x² - xy + 1 - ( -2x² + 6xy + 7 )
• m = 3x² - xy + 1 + 2x² - 6xy - 7
• m = 5x² - 7xy - 6