Solve 2x − 9 = 11

The solution of 2x − 9 = 11 is x = 10.

2x - 9 = 11\ \Rightarrow\ x = 10

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The lines y = 2x − 9 and y = 11 meet at x = 10. The solution of the equation is the x-coordinate of the point where the two sides are equal.

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.
$2x - 9 = 11$
2
Add 9 to both sides:
$2x - 9 + 9 = 11 + 9 \ \Rightarrow\ 2x = 20$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{20}{2} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$2\cdot10 - 9 = 20 - 9 = 11 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 9 = 11\ \Rightarrow\ x = 10 \]
\[ 2x - 9 = 11 \]
\[ 2x - 9 + 9 = 11 + 9 \ \Rightarrow\ 2x = 20 \]
\[ \frac{2x}{2} = \frac{20}{2} \ \Rightarrow\ x = 10 \]
\[ 2\cdot10 - 9 = 20 - 9 = 11 \checkmark \]

Trying values of x in 2x − 9 = 11

x	2x − 9	Equals 11?
8	7	no
9	9	no
10	11	yes
11	13	no
12	15	no

Questions

What is x in 2x − 9 = 11?

The solution of 2x − 9 = 11 is x = 10.

How do you solve 2x − 9 = 11?

Add 9 to both sides to get 2x = 20, then divide both sides by 2 to get x = 10.

How do I check the answer?

Replace x by 10: 2(10) − 9 = 11, which is 11.

Solve 2x − 9 = 11

How to work it out

Trying values of x in 2x − 9 = 11

Questions

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