Step-by-step explanation:
Answer:
Factorize 12 and 24
12 = 2 * 2 * 3
24 = 2 * 2 * 2 * 3
GCF = 2 * 2 * 3 = 12
12 + 24x = 12*1 + 12 * 2 *x
= 12*(1 + 2x)