Solve 9x + 3 = 75
The solution of 9x + 3 = 75 is x = 8.
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 3 from both sides:
- 3
Divide both sides by 9:
- 4
Check: put x = 8 back into the equation.
LaTeX source of the formulas on this page
\[ 9x + 3 = 75\ \Rightarrow\ x = 8 \]
\[ 9x + 3 = 75 \]
\[ 9x + 3 - 3 = 75 - 3 \ \Rightarrow\ 9x = 72 \]
\[ \frac{9x}{9} = \frac{72}{9} \ \Rightarrow\ x = 8 \]
\[ 9\cdot8 + 3 = 72 + 3 = 75 \checkmark \]Trying values of x in 9x + 3 = 75
| x | 9x + 3 | Equals 75? |
|---|---|---|
| 6 | 57 | no |
| 7 | 66 | no |
| 8 | 75 | yes |
| 9 | 84 | no |
| 10 | 93 | no |
Questions
What is x in 9x + 3 = 75?
The solution of 9x + 3 = 75 is x = 8.
How do you solve 9x + 3 = 75?
Subtract 3 from both sides to get 9x = 72, then divide both sides by 9 to get x = 8.
How do I check the answer?
Replace x by 8: 9(8) + 3 = 75, which is 75.