Solve 9x − 15 = 156

The solution of 9x − 15 = 156 is x = 19.

9x - 15 = 156\ \Rightarrow\ x = 19

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The lines y = 9x − 15 and y = 156 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.
$9x - 15 = 156$
2
Add 15 to both sides:
$9x - 15 + 15 = 156 + 15 \ \Rightarrow\ 9x = 171$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{171}{9} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$9\cdot19 - 15 = 171 - 15 = 156 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 15 = 156\ \Rightarrow\ x = 19 \]
\[ 9x - 15 = 156 \]
\[ 9x - 15 + 15 = 156 + 15 \ \Rightarrow\ 9x = 171 \]
\[ \frac{9x}{9} = \frac{171}{9} \ \Rightarrow\ x = 19 \]
\[ 9\cdot19 - 15 = 171 - 15 = 156 \checkmark \]

Trying values of x in 9x − 15 = 156

x	9x − 15	Equals 156?
17	138	no
18	147	no
19	156	yes
20	165	no
21	174	no

Questions

What is x in 9x − 15 = 156?

The solution of 9x − 15 = 156 is x = 19.

How do you solve 9x − 15 = 156?

Add 15 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) − 15 = 156, which is 156.

Solve 9x − 15 = 156

How to work it out

Trying values of x in 9x − 15 = 156

Questions

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