Solve 12x − 4 = 80

The solution of 12x − 4 = 80 is x = 7.

12x - 4 = 80\ \Rightarrow\ x = 7

Explain it step by step in chat Make a short video of it

The lines y = 12x − 4 and y = 80 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.
$12x - 4 = 80$
2
Add 4 to both sides:
$12x - 4 + 4 = 80 + 4 \ \Rightarrow\ 12x = 84$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{84}{12} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$12\cdot7 - 4 = 84 - 4 = 80 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 4 = 80\ \Rightarrow\ x = 7 \]
\[ 12x - 4 = 80 \]
\[ 12x - 4 + 4 = 80 + 4 \ \Rightarrow\ 12x = 84 \]
\[ \frac{12x}{12} = \frac{84}{12} \ \Rightarrow\ x = 7 \]
\[ 12\cdot7 - 4 = 84 - 4 = 80 \checkmark \]

Trying values of x in 12x − 4 = 80

x	12x − 4	Equals 80?
5	56	no
6	68	no
7	80	yes
8	92	no
9	104	no

Questions

What is x in 12x − 4 = 80?

The solution of 12x − 4 = 80 is x = 7.

How do you solve 12x − 4 = 80?

Add 4 to both sides to get 12x = 84, then divide both sides by 12 to get x = 7.

How do I check the answer?

Replace x by 7: 12(7) − 4 = 80, which is 80.

Solve 12x − 4 = 80

How to work it out

Trying values of x in 12x − 4 = 80

Questions

Similar equations