Solve 12x − 15 = 189

The solution of 12x − 15 = 189 is x = 17.

12x - 15 = 189\ \Rightarrow\ x = 17

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The lines y = 12x − 15 and y = 189 meet at x = 17. 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.
$12x - 15 = 189$
2
Add 15 to both sides:
$12x - 15 + 15 = 189 + 15 \ \Rightarrow\ 12x = 204$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{204}{12} \ \Rightarrow\ x = 17$
4
Check: put x = 17 back into the equation.
$12\cdot17 - 15 = 204 - 15 = 189 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 15 = 189\ \Rightarrow\ x = 17 \]
\[ 12x - 15 = 189 \]
\[ 12x - 15 + 15 = 189 + 15 \ \Rightarrow\ 12x = 204 \]
\[ \frac{12x}{12} = \frac{204}{12} \ \Rightarrow\ x = 17 \]
\[ 12\cdot17 - 15 = 204 - 15 = 189 \checkmark \]

Trying values of x in 12x − 15 = 189

x	12x − 15	Equals 189?
15	165	no
16	177	no
17	189	yes
18	201	no
19	213	no

Questions

What is x in 12x − 15 = 189?

The solution of 12x − 15 = 189 is x = 17.

How do you solve 12x − 15 = 189?

Add 15 to both sides to get 12x = 204, then divide both sides by 12 to get x = 17.

How do I check the answer?

Replace x by 17: 12(17) − 15 = 189, which is 189.

Solve 12x − 15 = 189

How to work it out

Trying values of x in 12x − 15 = 189

Questions

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