Solve 9x − 12 = 159

The solution of 9x − 12 = 159 is x = 19.

9x - 12 = 159\ \Rightarrow\ x = 19

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The lines y = 9x − 12 and y = 159 meet at x = 19. 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.
$9x - 12 = 159$
2
Add 12 to both sides:
$9x - 12 + 12 = 159 + 12 \ \Rightarrow\ 9x = 171$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{171}{9} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$9\cdot19 - 12 = 171 - 12 = 159 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 12 = 159\ \Rightarrow\ x = 19 \]
\[ 9x - 12 = 159 \]
\[ 9x - 12 + 12 = 159 + 12 \ \Rightarrow\ 9x = 171 \]
\[ \frac{9x}{9} = \frac{171}{9} \ \Rightarrow\ x = 19 \]
\[ 9\cdot19 - 12 = 171 - 12 = 159 \checkmark \]

Trying values of x in 9x − 12 = 159

x	9x − 12	Equals 159?
17	141	no
18	150	no
19	159	yes
20	168	no
21	177	no

Questions

What is x in 9x − 12 = 159?

The solution of 9x − 12 = 159 is x = 19.

How do you solve 9x − 12 = 159?

Add 12 to both sides to get 9x = 171, then divide both sides by 9 to get x = 19.

How do I check the answer?

Replace x by 19: 9(19) − 12 = 159, which is 159.

Solve 9x − 12 = 159

How to work it out

Trying values of x in 9x − 12 = 159

Questions

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