Solve 10x − 9 = 171

The solution of 10x − 9 = 171 is x = 18.

10x - 9 = 171\ \Rightarrow\ x = 18

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The lines y = 10x − 9 and y = 171 meet at x = 18. 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.
$10x - 9 = 171$
2
Add 9 to both sides:
$10x - 9 + 9 = 171 + 9 \ \Rightarrow\ 10x = 180$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{180}{10} \ \Rightarrow\ x = 18$
4
Check: put x = 18 back into the equation.
$10\cdot18 - 9 = 180 - 9 = 171 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 9 = 171\ \Rightarrow\ x = 18 \]
\[ 10x - 9 = 171 \]
\[ 10x - 9 + 9 = 171 + 9 \ \Rightarrow\ 10x = 180 \]
\[ \frac{10x}{10} = \frac{180}{10} \ \Rightarrow\ x = 18 \]
\[ 10\cdot18 - 9 = 180 - 9 = 171 \checkmark \]

Trying values of x in 10x − 9 = 171

x	10x − 9	Equals 171?
16	151	no
17	161	no
18	171	yes
19	181	no
20	191	no

Questions

What is x in 10x − 9 = 171?

The solution of 10x − 9 = 171 is x = 18.

How do you solve 10x − 9 = 171?

Add 9 to both sides to get 10x = 180, then divide both sides by 10 to get x = 18.

How do I check the answer?

Replace x by 18: 10(18) − 9 = 171, which is 171.

Solve 10x − 9 = 171

How to work it out

Trying values of x in 10x − 9 = 171

Questions

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