Solve 9x − 3 = 123

The solution of 9x − 3 = 123 is x = 14.

9x - 3 = 123\ \Rightarrow\ x = 14

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The lines y = 9x − 3 and y = 123 meet at x = 14. 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.
$9x - 3 = 123$
2
Add 3 to both sides:
$9x - 3 + 3 = 123 + 3 \ \Rightarrow\ 9x = 126$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{126}{9} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$9\cdot14 - 3 = 126 - 3 = 123 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 3 = 123\ \Rightarrow\ x = 14 \]
\[ 9x - 3 = 123 \]
\[ 9x - 3 + 3 = 123 + 3 \ \Rightarrow\ 9x = 126 \]
\[ \frac{9x}{9} = \frac{126}{9} \ \Rightarrow\ x = 14 \]
\[ 9\cdot14 - 3 = 126 - 3 = 123 \checkmark \]

Trying values of x in 9x − 3 = 123

x	9x − 3	Equals 123?
12	105	no
13	114	no
14	123	yes
15	132	no
16	141	no

Questions

What is x in 9x − 3 = 123?

The solution of 9x − 3 = 123 is x = 14.

How do you solve 9x − 3 = 123?

Add 3 to both sides to get 9x = 126, then divide both sides by 9 to get x = 14.

How do I check the answer?

Replace x by 14: 9(14) − 3 = 123, which is 123.

Solve 9x − 3 = 123

How to work it out

Trying values of x in 9x − 3 = 123

Questions

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