Solve 2x ā 1 = ā9
The solution of 2x ā 1 = ā9 is x = -4.
How to work it out
- 1
The goal is to get x alone. Undo the operations in the opposite order: first the subtraction, then the multiplication.
- 2
Add 1 to both sides:
- 3
Divide both sides by 2:
- 4
Check: put x = -4 back into the equation.
LaTeX source of the formulas on this page
\[ 2x - 1 = -9\ \Rightarrow\ x = -4 \]
\[ 2x - 1 = -9 \]
\[ 2x - 1 + 1 = -9 + 1 \ \Rightarrow\ 2x = -8 \]
\[ \frac{2x}{2} = \frac{-8}{2} \ \Rightarrow\ x = -4 \]
\[ 2\cdot(-4) - 1 = -8 - 1 = -9 \checkmark \]Trying values of x in 2x ā 1 = ā9
| x | 2x ā 1 | Equals -9? |
|---|---|---|
| -6 | -13 | no |
| -5 | -11 | no |
| -4 | -9 | yes |
| -3 | -7 | no |
| -2 | -5 | no |
Questions
What is x in 2x ā 1 = ā9?
The solution of 2x ā 1 = ā9 is x = -4.
How do you solve 2x ā 1 = ā9?
Add 1 to both sides to get 2x = -8, then divide both sides by 2 to get x = -4.
How do I check the answer?
Replace x by -4: 2(-4) ā 1 = -9, which is -9.