Solve 9x + 12 = 75
The solution of 9x + 12 = 75 is x = 7.
How to work it out
- 1
The goal is to get x alone. Undo the operations in the opposite order: first the addition, then the multiplication.
- 2
Subtract 12 from both sides:
- 3
Divide both sides by 9:
- 4
Check: put x = 7 back into the equation.
LaTeX source of the formulas on this page
\[ 9x + 12 = 75\ \Rightarrow\ x = 7 \]
\[ 9x + 12 = 75 \]
\[ 9x + 12 - 12 = 75 - 12 \ \Rightarrow\ 9x = 63 \]
\[ \frac{9x}{9} = \frac{63}{9} \ \Rightarrow\ x = 7 \]
\[ 9\cdot7 + 12 = 63 + 12 = 75 \checkmark \]Trying values of x in 9x + 12 = 75
| x | 9x + 12 | Equals 75? |
|---|---|---|
| 5 | 57 | no |
| 6 | 66 | no |
| 7 | 75 | yes |
| 8 | 84 | no |
| 9 | 93 | no |
Questions
What is x in 9x + 12 = 75?
The solution of 9x + 12 = 75 is x = 7.
How do you solve 9x + 12 = 75?
Subtract 12 from both sides to get 9x = 63, then divide both sides by 9 to get x = 7.
How do I check the answer?
Replace x by 7: 9(7) + 12 = 75, which is 75.