Solve 9x − 10 = 170

The solution of 9x − 10 = 170 is x = 20.

9x - 10 = 170\ \Rightarrow\ x = 20

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The lines y = 9x − 10 and y = 170 meet at x = 20. 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.
$9x - 10 = 170$
2
Add 10 to both sides:
$9x - 10 + 10 = 170 + 10 \ \Rightarrow\ 9x = 180$
3
Divide both sides by 9:
$\frac{9x}{9} = \frac{180}{9} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$9\cdot20 - 10 = 180 - 10 = 170 \checkmark$

LaTeX source of the formulas on this page

\[ 9x - 10 = 170\ \Rightarrow\ x = 20 \]
\[ 9x - 10 = 170 \]
\[ 9x - 10 + 10 = 170 + 10 \ \Rightarrow\ 9x = 180 \]
\[ \frac{9x}{9} = \frac{180}{9} \ \Rightarrow\ x = 20 \]
\[ 9\cdot20 - 10 = 180 - 10 = 170 \checkmark \]

Trying values of x in 9x − 10 = 170

x	9x − 10	Equals 170?
18	152	no
19	161	no
20	170	yes
21	179	no
22	188	no

Questions

What is x in 9x − 10 = 170?

The solution of 9x − 10 = 170 is x = 20.

How do you solve 9x − 10 = 170?

Add 10 to both sides to get 9x = 180, then divide both sides by 9 to get x = 20.

How do I check the answer?

Replace x by 20: 9(20) − 10 = 170, which is 170.

Solve 9x − 10 = 170

How to work it out

Trying values of x in 9x − 10 = 170

Questions

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