Answer:
x = -1
Step-by-step explanation:
-4(3x-7) =40
Divide each side by -4
-4(3x-7)/-4 =40/-4
3x-7 = -10
Add 7 to each side
3x-7+7 = -10+7
3x = -3
Divide each side by 3
3x/3 = -3/3
x = -1
It would cost $35 because 10.50 divided by 3 = 3.5x10=35
The formula for that area would be A=1/2xbxh so you would do A=1/2x3.5x3 and that equals 5.25