Question

When three times a number is decreased by 7, the result is 20. What is the number?

The number is?

Answer 1

3x-7=20
3x=27
x=9

number is 9

Answer 2

The number is 9

Explanation:

• Let the number be x

`{ \tt{3x - 7 = 20}} \\`

» Add 7 to either sides following addition rule of equality:

`{ \tt{(3x - 7){ \red{ + 7}} = 20{ \red{ + 7}}}} \\ { \tt{3x = 27}}`

» Divide either sides by 27:

`{ \tt{ \frac{3x}{ \blue{3 }} = \frac{27}{ \blue{3}} }} \\ \\ { \tt{x = 9}}`