Question

What must be added to 3x-7 to make x^2 +4x-1 ?

Answer 1

 x²+4x-1 - (3x - 7) = x² + 4x - 1 - 3x +7 = x² + x + 6

x² + x + 6 should be added to 3x - 7  to make  x²+4x-1.