Solve 9x + 2 = 128
The solution of 9x + 2 = 128 is x = 14.
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 2 from both sides:
- 3
Divide both sides by 9:
- 4
Check: put x = 14 back into the equation.
LaTeX source of the formulas on this page
\[ 9x + 2 = 128\ \Rightarrow\ x = 14 \]
\[ 9x + 2 = 128 \]
\[ 9x + 2 - 2 = 128 - 2 \ \Rightarrow\ 9x = 126 \]
\[ \frac{9x}{9} = \frac{126}{9} \ \Rightarrow\ x = 14 \]
\[ 9\cdot14 + 2 = 126 + 2 = 128 \checkmark \]Trying values of x in 9x + 2 = 128
| x | 9x + 2 | Equals 128? |
|---|---|---|
| 12 | 110 | no |
| 13 | 119 | no |
| 14 | 128 | yes |
| 15 | 137 | no |
| 16 | 146 | no |
Questions
What is x in 9x + 2 = 128?
The solution of 9x + 2 = 128 is x = 14.
How do you solve 9x + 2 = 128?
Subtract 2 from both sides to get 9x = 126, then divide both sides by 9 to get x = 14.
How do I check the answer?
Replace x by 14: 9(14) + 2 = 128, which is 128.