Solve 2x + 9 = 23

The solution of 2x + 9 = 23 is x = 7.

2x + 9 = 23\ \Rightarrow\ x = 7

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The lines y = 2x + 9 and y = 23 meet at x = 7. 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 addition, then the multiplication.
$2x + 9 = 23$
2
Subtract 9 from both sides:
$2x + 9 - 9 = 23 - 9 \ \Rightarrow\ 2x = 14$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{14}{2} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$2\cdot7 + 9 = 14 + 9 = 23 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 9 = 23\ \Rightarrow\ x = 7 \]
\[ 2x + 9 = 23 \]
\[ 2x + 9 - 9 = 23 - 9 \ \Rightarrow\ 2x = 14 \]
\[ \frac{2x}{2} = \frac{14}{2} \ \Rightarrow\ x = 7 \]
\[ 2\cdot7 + 9 = 14 + 9 = 23 \checkmark \]

Trying values of x in 2x + 9 = 23

x	2x + 9	Equals 23?
5	19	no
6	21	no
7	23	yes
8	25	no
9	27	no

Questions

What is x in 2x + 9 = 23?

The solution of 2x + 9 = 23 is x = 7.

How do you solve 2x + 9 = 23?

Subtract 9 from both sides to get 2x = 14, then divide both sides by 2 to get x = 7.

How do I check the answer?

Replace x by 7: 2(7) + 9 = 23, which is 23.

Solve 2x + 9 = 23

How to work it out

Trying values of x in 2x + 9 = 23

Questions

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