Solve 12x − 9 = 207

The solution of 12x − 9 = 207 is x = 18.

12x - 9 = 207\ \Rightarrow\ x = 18

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The lines y = 12x − 9 and y = 207 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.
$12x - 9 = 207$
2
Add 9 to both sides:
$12x - 9 + 9 = 207 + 9 \ \Rightarrow\ 12x = 216$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{216}{12} \ \Rightarrow\ x = 18$
4
Check: put x = 18 back into the equation.
$12\cdot18 - 9 = 216 - 9 = 207 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 9 = 207\ \Rightarrow\ x = 18 \]
\[ 12x - 9 = 207 \]
\[ 12x - 9 + 9 = 207 + 9 \ \Rightarrow\ 12x = 216 \]
\[ \frac{12x}{12} = \frac{216}{12} \ \Rightarrow\ x = 18 \]
\[ 12\cdot18 - 9 = 216 - 9 = 207 \checkmark \]

Trying values of x in 12x − 9 = 207

x	12x − 9	Equals 207?
16	183	no
17	195	no
18	207	yes
19	219	no
20	231	no

Questions

What is x in 12x − 9 = 207?

The solution of 12x − 9 = 207 is x = 18.

How do you solve 12x − 9 = 207?

Add 9 to both sides to get 12x = 216, then divide both sides by 12 to get x = 18.

How do I check the answer?

Replace x by 18: 12(18) − 9 = 207, which is 207.

Solve 12x − 9 = 207

How to work it out

Trying values of x in 12x − 9 = 207

Questions

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