Solve 4x + 3 = 51
The solution of 4x + 3 = 51 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 3 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
\[ 4x + 3 = 51\ \Rightarrow\ x = 12 \]
\[ 4x + 3 = 51 \]
\[ 4x + 3 - 3 = 51 - 3 \ \Rightarrow\ 4x = 48 \]
\[ \frac{4x}{4} = \frac{48}{4} \ \Rightarrow\ x = 12 \]
\[ 4\cdot12 + 3 = 48 + 3 = 51 \checkmark \]Trying values of x in 4x + 3 = 51
| x | 4x + 3 | Equals 51? |
|---|---|---|
| 10 | 43 | no |
| 11 | 47 | no |
| 12 | 51 | yes |
| 13 | 55 | no |
| 14 | 59 | no |
Questions
What is x in 4x + 3 = 51?
The solution of 4x + 3 = 51 is x = 12.
How do you solve 4x + 3 = 51?
Subtract 3 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) + 3 = 51, which is 51.