Solve 2x − 9 = 27

The solution of 2x − 9 = 27 is x = 18.

2x - 9 = 27\ \Rightarrow\ x = 18

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The lines y = 2x − 9 and y = 27 meet at x = 18. 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.
$2x - 9 = 27$
2
Add 9 to both sides:
$2x - 9 + 9 = 27 + 9 \ \Rightarrow\ 2x = 36$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{36}{2} \ \Rightarrow\ x = 18$
4
Check: put x = 18 back into the equation.
$2\cdot18 - 9 = 36 - 9 = 27 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 9 = 27\ \Rightarrow\ x = 18 \]
\[ 2x - 9 = 27 \]
\[ 2x - 9 + 9 = 27 + 9 \ \Rightarrow\ 2x = 36 \]
\[ \frac{2x}{2} = \frac{36}{2} \ \Rightarrow\ x = 18 \]
\[ 2\cdot18 - 9 = 36 - 9 = 27 \checkmark \]

Trying values of x in 2x − 9 = 27

x	2x − 9	Equals 27?
16	23	no
17	25	no
18	27	yes
19	29	no
20	31	no

Questions

What is x in 2x − 9 = 27?

The solution of 2x − 9 = 27 is x = 18.

How do you solve 2x − 9 = 27?

Add 9 to both sides to get 2x = 36, then divide both sides by 2 to get x = 18.

How do I check the answer?

Replace x by 18: 2(18) − 9 = 27, which is 27.

Solve 2x − 9 = 27

How to work it out

Trying values of x in 2x − 9 = 27

Questions

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