Solve 3x − 9 = −3

The solution of 3x − 9 = −3 is x = 2.

3x - 9 = -3\ \Rightarrow\ x = 2

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The lines y = 3x − 9 and y = -3 meet at x = 2. 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.
$3x - 9 = -3$
2
Add 9 to both sides:
$3x - 9 + 9 = -3 + 9 \ \Rightarrow\ 3x = 6$
3
Divide both sides by 3:
$\frac{3x}{3} = \frac{6}{3} \ \Rightarrow\ x = 2$
4
Check: put x = 2 back into the equation.
$3\cdot2 - 9 = 6 - 9 = -3 \checkmark$

LaTeX source of the formulas on this page

\[ 3x - 9 = -3\ \Rightarrow\ x = 2 \]
\[ 3x - 9 = -3 \]
\[ 3x - 9 + 9 = -3 + 9 \ \Rightarrow\ 3x = 6 \]
\[ \frac{3x}{3} = \frac{6}{3} \ \Rightarrow\ x = 2 \]
\[ 3\cdot2 - 9 = 6 - 9 = -3 \checkmark \]

Trying values of x in 3x − 9 = −3

x	3x − 9	Equals -3?
0	-9	no
1	-6	no
2	-3	yes
3	0	no
4	3	no

Questions

What is x in 3x − 9 = −3?

The solution of 3x − 9 = −3 is x = 2.

How do you solve 3x − 9 = −3?

Add 9 to both sides to get 3x = 6, then divide both sides by 3 to get x = 2.

How do I check the answer?

Replace x by 2: 3(2) − 9 = -3, which is -3.

Solve 3x − 9 = −3

How to work it out

Trying values of x in 3x − 9 = −3

Questions

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