Question

Which is an equivalent expression for 21a+35?

Select one:

7(3a+5)

21(a+35)

7(3a+35)

Answer 1

7(3a + 5)

Explanation:

Rewrite 21 as 7 · 3

Rewrite 35 as 7 · 5

Therefore,

⇒ 21a + 35 = 7 · 3a + 7 · 5

Factor out common term 7:

⇒ 7 · 3a + 7 · 5 = 7(3a + 5)