Solve 12x − 15 = 213

The solution of 12x − 15 = 213 is x = 19.

12x - 15 = 213\ \Rightarrow\ x = 19

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The lines y = 12x − 15 and y = 213 meet at x = 19. 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.
$12x - 15 = 213$
2
Add 15 to both sides:
$12x - 15 + 15 = 213 + 15 \ \Rightarrow\ 12x = 228$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{228}{12} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$12\cdot19 - 15 = 228 - 15 = 213 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 15 = 213\ \Rightarrow\ x = 19 \]
\[ 12x - 15 = 213 \]
\[ 12x - 15 + 15 = 213 + 15 \ \Rightarrow\ 12x = 228 \]
\[ \frac{12x}{12} = \frac{228}{12} \ \Rightarrow\ x = 19 \]
\[ 12\cdot19 - 15 = 228 - 15 = 213 \checkmark \]

Trying values of x in 12x − 15 = 213

x	12x − 15	Equals 213?
17	189	no
18	201	no
19	213	yes
20	225	no
21	237	no

Questions

What is x in 12x − 15 = 213?

The solution of 12x − 15 = 213 is x = 19.

How do you solve 12x − 15 = 213?

Add 15 to both sides to get 12x = 228, then divide both sides by 12 to get x = 19.

How do I check the answer?

Replace x by 19: 12(19) − 15 = 213, which is 213.

Solve 12x − 15 = 213

How to work it out

Trying values of x in 12x − 15 = 213

Questions

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