Question

what must be added to 2x³-4x+9to get 5x³-13

Answer 1

Let P=2x3−4x+9 and Q=5x3−13P+R=Q2x3−4x+9+R=5x3−13
R=5x3−13−(2x3−4x+9)
R=5x3−13−2x3+4x−9R=3x3+4x−22

Answer 2

$< ANSWER > \\ Let \: the \: number \: be \: y \\ so \: A/Q$

$2 {x}^{3} -4x+9 + y = 5 {x}^{3} -13 \\ y = 5 {x}^{3} - 13 - 2 {x}^{3} + 4x - 9 \\ y = 3 {x}^{3} + 4x - 22$

$HOPE \: IT \: HELPS \: YOU$