Answer:
Alex will need 14 bags
Explanation:
B= 4(2x+7)+3(2x+7)
and
2x+7=2
First, we should solve the second equation to obtain x:
2x+7=2
2x=2-7
x= -5/2
Then, we use this answer to calculate B:
B=4(2(-5/2)+7)+3(2)
B=4(-5+7)+6
B=4(2)+6
B=8+6
B=14
Alex will need 14 bags