Question

What is the value of a in the equation 5a – 10b = 45, when b = 3?

Answer 1

If b = 3 you substitute al the b's on the equation by 3:

5a - 10(3) = 45 - you substitute b for 3

5a - 30 = 45 - you do 10 * 3

5a = 45 + 30 - you move 30 to the right side of the equation

5a = 75 - you do 45 + 30

a =
`(75)/(5)` - you take 5 to the right side of the equation

a = 15

Hope it helped,

Happy homework/ study/ exam!

Answer 2

5a – 10b = 45

Substitute b = 3 into the equation

5a – 10(3) = 45

5a - 30 = 45

5a = 75

a = 15

Answer: a = 15