Solve 12x − 9 = 3

The solution of 12x − 9 = 3 is x = 1.

12x - 9 = 3\ \Rightarrow\ x = 1

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The lines y = 12x − 9 and y = 3 meet at x = 1. 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.
$12x - 9 = 3$
2
Add 9 to both sides:
$12x - 9 + 9 = 3 + 9 \ \Rightarrow\ 12x = 12$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{12}{12} \ \Rightarrow\ x = 1$
4
Check: put x = 1 back into the equation.
$12\cdot1 - 9 = 12 - 9 = 3 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 9 = 3\ \Rightarrow\ x = 1 \]
\[ 12x - 9 = 3 \]
\[ 12x - 9 + 9 = 3 + 9 \ \Rightarrow\ 12x = 12 \]
\[ \frac{12x}{12} = \frac{12}{12} \ \Rightarrow\ x = 1 \]
\[ 12\cdot1 - 9 = 12 - 9 = 3 \checkmark \]

Trying values of x in 12x − 9 = 3

x	12x − 9	Equals 3?
-1	-21	no
0	-9	no
1	3	yes
2	15	no
3	27	no

Questions

What is x in 12x − 9 = 3?

The solution of 12x − 9 = 3 is x = 1.

How do you solve 12x − 9 = 3?

Add 9 to both sides to get 12x = 12, then divide both sides by 12 to get x = 1.

How do I check the answer?

Replace x by 1: 12(1) − 9 = 3, which is 3.

Solve 12x − 9 = 3

How to work it out

Trying values of x in 12x − 9 = 3

Questions

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