Answer:
7a+28b=21
Step-by-step explanation:
7×a=7a
7×-3= -21
7×+4b=+28b
so....
7a-21+28b=0
Area= Length * Width
3*4= 12
Answer: 12ft^2
Me no good at math :(
I big dumb
C. The 40th customer
Answer: the answer should be D