Solve 4x + 9 = 57
The solution of 4x + 9 = 57 is x = 12.
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 9 from both sides:
- 3
Divide both sides by 4:
- 4
Check: put x = 12 back into the equation.
LaTeX source of the formulas on this page
\[ 4x + 9 = 57\ \Rightarrow\ x = 12 \]
\[ 4x + 9 = 57 \]
\[ 4x + 9 - 9 = 57 - 9 \ \Rightarrow\ 4x = 48 \]
\[ \frac{4x}{4} = \frac{48}{4} \ \Rightarrow\ x = 12 \]
\[ 4\cdot12 + 9 = 48 + 9 = 57 \checkmark \]Trying values of x in 4x + 9 = 57
| x | 4x + 9 | Equals 57? |
|---|---|---|
| 10 | 49 | no |
| 11 | 53 | no |
| 12 | 57 | yes |
| 13 | 61 | no |
| 14 | 65 | no |
Questions
What is x in 4x + 9 = 57?
The solution of 4x + 9 = 57 is x = 12.
How do you solve 4x + 9 = 57?
Subtract 9 from both sides to get 4x = 48, then divide both sides by 4 to get x = 12.
How do I check the answer?
Replace x by 12: 4(12) + 9 = 57, which is 57.