Solve 2x + 12 = 40

The solution of 2x + 12 = 40 is x = 14.

2x + 12 = 40\ \Rightarrow\ x = 14

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The lines y = 2x + 12 and y = 40 meet at x = 14. 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 addition, then the multiplication.
$2x + 12 = 40$
2
Subtract 12 from both sides:
$2x + 12 - 12 = 40 - 12 \ \Rightarrow\ 2x = 28$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{28}{2} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$2\cdot14 + 12 = 28 + 12 = 40 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 12 = 40\ \Rightarrow\ x = 14 \]
\[ 2x + 12 = 40 \]
\[ 2x + 12 - 12 = 40 - 12 \ \Rightarrow\ 2x = 28 \]
\[ \frac{2x}{2} = \frac{28}{2} \ \Rightarrow\ x = 14 \]
\[ 2\cdot14 + 12 = 28 + 12 = 40 \checkmark \]

Trying values of x in 2x + 12 = 40

x	2x + 12	Equals 40?
12	36	no
13	38	no
14	40	yes
15	42	no
16	44	no

Questions

What is x in 2x + 12 = 40?

The solution of 2x + 12 = 40 is x = 14.

How do you solve 2x + 12 = 40?

Subtract 12 from both sides to get 2x = 28, then divide both sides by 2 to get x = 14.

How do I check the answer?

Replace x by 14: 2(14) + 12 = 40, which is 40.

Solve 2x + 12 = 40

How to work it out

Trying values of x in 2x + 12 = 40

Questions

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