Solve 8x − 12 = 28

The solution of 8x − 12 = 28 is x = 5.

8x - 12 = 28\ \Rightarrow\ x = 5

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The lines y = 8x − 12 and y = 28 meet at x = 5. 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.
$8x - 12 = 28$
2
Add 12 to both sides:
$8x - 12 + 12 = 28 + 12 \ \Rightarrow\ 8x = 40$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{40}{8} \ \Rightarrow\ x = 5$
4
Check: put x = 5 back into the equation.
$8\cdot5 - 12 = 40 - 12 = 28 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 12 = 28\ \Rightarrow\ x = 5 \]
\[ 8x - 12 = 28 \]
\[ 8x - 12 + 12 = 28 + 12 \ \Rightarrow\ 8x = 40 \]
\[ \frac{8x}{8} = \frac{40}{8} \ \Rightarrow\ x = 5 \]
\[ 8\cdot5 - 12 = 40 - 12 = 28 \checkmark \]

Trying values of x in 8x − 12 = 28

x	8x − 12	Equals 28?
3	12	no
4	20	no
5	28	yes
6	36	no
7	44	no

Questions

What is x in 8x − 12 = 28?

The solution of 8x − 12 = 28 is x = 5.

How do you solve 8x − 12 = 28?

Add 12 to both sides to get 8x = 40, then divide both sides by 8 to get x = 5.

How do I check the answer?

Replace x by 5: 8(5) − 12 = 28, which is 28.

Solve 8x − 12 = 28

How to work it out

Trying values of x in 8x − 12 = 28

Questions

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