Solve 9x − 9 = 144

The solution of 9x − 9 = 144 is x = 17.

9x - 9 = 144\ \Rightarrow\ x = 17

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The lines y = 9x − 9 and y = 144 meet at x = 17. 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.
$9x - 9 = 144$
2
Add 9 to both sides:
$9x - 9 + 9 = 144 + 9 \ \Rightarrow\ 9x = 153$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{153}{9} \ \Rightarrow\ x = 17$
4
Check: put x = 17 back into the equation.
$9\cdot17 - 9 = 153 - 9 = 144 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 9 = 144\ \Rightarrow\ x = 17 \]
\[ 9x - 9 = 144 \]
\[ 9x - 9 + 9 = 144 + 9 \ \Rightarrow\ 9x = 153 \]
\[ \frac{9x}{9} = \frac{153}{9} \ \Rightarrow\ x = 17 \]
\[ 9\cdot17 - 9 = 153 - 9 = 144 \checkmark \]

Trying values of x in 9x − 9 = 144

x	9x − 9	Equals 144?
15	126	no
16	135	no
17	144	yes
18	153	no
19	162	no

Questions

What is x in 9x − 9 = 144?

The solution of 9x − 9 = 144 is x = 17.

How do you solve 9x − 9 = 144?

Add 9 to both sides to get 9x = 153, then divide both sides by 9 to get x = 17.

How do I check the answer?

Replace x by 17: 9(17) − 9 = 144, which is 144.

Solve 9x − 9 = 144

How to work it out

Trying values of x in 9x − 9 = 144

Questions

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