Answer:
4(7+3)
Step-by-step explanation:
28 and 12 are both divisible by 4.
28 ÷ 4 = 7
12 ÷ 4 = 3
5 is a factor
45s–35
45s = 5*9*s
35 = 5*7
45s–35 = 5(9s-7)