Solve 2x − 12 = 28

The solution of 2x − 12 = 28 is x = 20.

2x - 12 = 28\ \Rightarrow\ x = 20

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The lines y = 2x − 12 and y = 28 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.
$2x - 12 = 28$
2
Add 12 to both sides:
$2x - 12 + 12 = 28 + 12 \ \Rightarrow\ 2x = 40$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{40}{2} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$2\cdot20 - 12 = 40 - 12 = 28 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 12 = 28\ \Rightarrow\ x = 20 \]
\[ 2x - 12 = 28 \]
\[ 2x - 12 + 12 = 28 + 12 \ \Rightarrow\ 2x = 40 \]
\[ \frac{2x}{2} = \frac{40}{2} \ \Rightarrow\ x = 20 \]
\[ 2\cdot20 - 12 = 40 - 12 = 28 \checkmark \]

Trying values of x in 2x − 12 = 28

x	2x − 12	Equals 28?
18	24	no
19	26	no
20	28	yes
21	30	no
22	32	no

Questions

What is x in 2x − 12 = 28?

The solution of 2x − 12 = 28 is x = 20.

How do you solve 2x − 12 = 28?

Add 12 to both sides to get 2x = 40, then divide both sides by 2 to get x = 20.

How do I check the answer?

Replace x by 20: 2(20) − 12 = 28, which is 28.

Solve 2x − 12 = 28

How to work it out

Trying values of x in 2x − 12 = 28

Questions

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