Question

What must be added to 12x3 - 4x2 + 3x + 7 to make the sum x3 + 2x2 - 3x +

Answer 1

Answer:

let y must be added, then

$12 {x}^{3 } \: - 4 {x }^{2} + 3x + 7 + y = {x}^{3 } + 2 {x}^{2} - 3x \\ y = {x}^{3 } - {12x}^{3} + 2 {x}^{2} + 4 {x}^{2} - 3x - 3x - 7 \\ y = - 11 {x}^{3} + 6 {x}^{2} - 6x - 7$