"If an integer n is odd, then n+1 must be even."

Yes .An integer n is odd if and only if n + 1 is even.

Step-by-step explanation:

Proof.

We first prove ( =⇒ ). n +1=2k +1+1 = 2k + 2 = 2(k + 1).

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10

5x+10 is the correct one

hope this