Solve 4x − 12 = 16

The solution of 4x − 12 = 16 is x = 7.

4x - 12 = 16\ \Rightarrow\ x = 7

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The lines y = 4x − 12 and y = 16 meet at x = 7. 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.
$4x - 12 = 16$
2
Add 12 to both sides:
$4x - 12 + 12 = 16 + 12 \ \Rightarrow\ 4x = 28$
3
Divide both sides by 4:
$\frac{4x}{4} = \frac{28}{4} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$4\cdot7 - 12 = 28 - 12 = 16 \checkmark$

LaTeX source of the formulas on this page

\[ 4x - 12 = 16\ \Rightarrow\ x = 7 \]
\[ 4x - 12 = 16 \]
\[ 4x - 12 + 12 = 16 + 12 \ \Rightarrow\ 4x = 28 \]
\[ \frac{4x}{4} = \frac{28}{4} \ \Rightarrow\ x = 7 \]
\[ 4\cdot7 - 12 = 28 - 12 = 16 \checkmark \]

Trying values of x in 4x − 12 = 16

x	4x − 12	Equals 16?
5	8	no
6	12	no
7	16	yes
8	20	no
9	24	no

Questions

What is x in 4x − 12 = 16?

The solution of 4x − 12 = 16 is x = 7.

How do you solve 4x − 12 = 16?

Add 12 to both sides to get 4x = 28, then divide both sides by 4 to get x = 7.

How do I check the answer?

Replace x by 7: 4(7) − 12 = 16, which is 16.

Solve 4x − 12 = 16

How to work it out

Trying values of x in 4x − 12 = 16

Questions

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