Solve 3x + 15 = 48
The solution of 3x + 15 = 48 is x = 11.
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 15 from both sides:
- 3
Divide both sides by 3:
- 4
Check: put x = 11 back into the equation.
LaTeX source of the formulas on this page
\[ 3x + 15 = 48\ \Rightarrow\ x = 11 \]
\[ 3x + 15 = 48 \]
\[ 3x + 15 - 15 = 48 - 15 \ \Rightarrow\ 3x = 33 \]
\[ \frac{3x}{3} = \frac{33}{3} \ \Rightarrow\ x = 11 \]
\[ 3\cdot11 + 15 = 33 + 15 = 48 \checkmark \]Trying values of x in 3x + 15 = 48
| x | 3x + 15 | Equals 48? |
|---|---|---|
| 9 | 42 | no |
| 10 | 45 | no |
| 11 | 48 | yes |
| 12 | 51 | no |
| 13 | 54 | no |
Questions
What is x in 3x + 15 = 48?
The solution of 3x + 15 = 48 is x = 11.
How do you solve 3x + 15 = 48?
Subtract 15 from both sides to get 3x = 33, then divide both sides by 3 to get x = 11.
How do I check the answer?
Replace x by 11: 3(11) + 15 = 48, which is 48.