Solve 9x − 15 = 3

The solution of 9x − 15 = 3 is x = 2.

9x - 15 = 3\ \Rightarrow\ x = 2

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The lines y = 9x − 15 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.
$9x - 15 = 3$
2
Add 15 to both sides:
$9x - 15 + 15 = 3 + 15 \ \Rightarrow\ 9x = 18$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{18}{9} \ \Rightarrow\ x = 2$
4
Check: put x = 2 back into the equation.
$9\cdot2 - 15 = 18 - 15 = 3 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 15 = 3\ \Rightarrow\ x = 2 \]
\[ 9x - 15 = 3 \]
\[ 9x - 15 + 15 = 3 + 15 \ \Rightarrow\ 9x = 18 \]
\[ \frac{9x}{9} = \frac{18}{9} \ \Rightarrow\ x = 2 \]
\[ 9\cdot2 - 15 = 18 - 15 = 3 \checkmark \]

Trying values of x in 9x − 15 = 3

x	9x − 15	Equals 3?
0	-15	no
1	-6	no
2	3	yes
3	12	no
4	21	no

Questions

What is x in 9x − 15 = 3?

The solution of 9x − 15 = 3 is x = 2.

How do you solve 9x − 15 = 3?

Add 15 to both sides to get 9x = 18, then divide both sides by 9 to get x = 2.

How do I check the answer?

Replace x by 2: 9(2) − 15 = 3, which is 3.

Solve 9x − 15 = 3

How to work it out

Trying values of x in 9x − 15 = 3

Questions

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