Question

What is undistributing?

Answer 1

Multiplication is said to *distribute* over addition if a\*b + a\*c = a*\(b + c). It’s clear that both 4 and 18 are even numbers, meaning that 2 is a factor of both. Therefore 4x + 18 = 2\*2\*x + 2\*9 = 2\*(2x + 9).