Question

If a = 4 and 5a(2b – 3a) = 40, what is the value of b?

a. 6

b. 7

c. 10

d. 12

Answer 1

b=7

Explanation:

5a(2b – 3a) = 40

Let a=4

5*4(2b-3*4) = 40

20(2b-12) = 40

Divide each side by 20

20/20 (2b-12) = 40/20

2b-12 =2

Add 12 to each side

2b-12+12 = 2+12

2b = 14

Divide by 2

2b/2 = 14/2

b = 7