Answer:
38 packages of erasers
Step-by-step explanation:
Divide 149 by 4 to determine the amount of packs
this is gives you 37.25, but you can't have a 0.25 of a package
therefore you would need 38 to compensate that 0.25 of a package
0
2x-x+7 = x+3+4
2x-x-x = -7+3+4
2x-2x = -4+4
0 = 0
x=63/8
9/8=x/7
or, 9*7=x*8
or, 63=8x