Answer:
Step-by-step explanation:
[tex]4a+7b+3a-2b\qquad\text{combine like terms}\\\\=(4a+3a)+(7b-2b)\\\\=7a+5b\qquad\text{put a = 5 and b = -3 to the expression}\\\\7(5)+5(-3)=35-15=20[/tex]
