Solve 10x − 15 = 165

The solution of 10x − 15 = 165 is x = 18.

10x - 15 = 165\ \Rightarrow\ x = 18

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The lines y = 10x − 15 and y = 165 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.
$10x - 15 = 165$
2
Add 15 to both sides:
$10x - 15 + 15 = 165 + 15 \ \Rightarrow\ 10x = 180$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{180}{10} \ \Rightarrow\ x = 18$
4
Check: put x = 18 back into the equation.
$10\cdot18 - 15 = 180 - 15 = 165 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 15 = 165\ \Rightarrow\ x = 18 \]
\[ 10x - 15 = 165 \]
\[ 10x - 15 + 15 = 165 + 15 \ \Rightarrow\ 10x = 180 \]
\[ \frac{10x}{10} = \frac{180}{10} \ \Rightarrow\ x = 18 \]
\[ 10\cdot18 - 15 = 180 - 15 = 165 \checkmark \]

Trying values of x in 10x − 15 = 165

x	10x − 15	Equals 165?
16	145	no
17	155	no
18	165	yes
19	175	no
20	185	no

Questions

What is x in 10x − 15 = 165?

The solution of 10x − 15 = 165 is x = 18.

How do you solve 10x − 15 = 165?

Add 15 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) − 15 = 165, which is 165.

Solve 10x − 15 = 165

How to work it out

Trying values of x in 10x − 15 = 165

Questions

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