Solve 6x − 6 = 78

The solution of 6x − 6 = 78 is x = 14.

6x - 6 = 78\ \Rightarrow\ x = 14

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The lines y = 6x − 6 and y = 78 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 subtraction, then the multiplication.
$6x - 6 = 78$
2
Add 6 to both sides:
$6x - 6 + 6 = 78 + 6 \ \Rightarrow\ 6x = 84$
3
Divide both sides by 6:
$\frac{6x}{6} = \frac{84}{6} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$6\cdot14 - 6 = 84 - 6 = 78 \checkmark$

LaTeX source of the formulas on this page

\[ 6x - 6 = 78\ \Rightarrow\ x = 14 \]
\[ 6x - 6 = 78 \]
\[ 6x - 6 + 6 = 78 + 6 \ \Rightarrow\ 6x = 84 \]
\[ \frac{6x}{6} = \frac{84}{6} \ \Rightarrow\ x = 14 \]
\[ 6\cdot14 - 6 = 84 - 6 = 78 \checkmark \]

Trying values of x in 6x − 6 = 78

x	6x − 6	Equals 78?
12	66	no
13	72	no
14	78	yes
15	84	no
16	90	no

Questions

What is x in 6x − 6 = 78?

The solution of 6x − 6 = 78 is x = 14.

How do you solve 6x − 6 = 78?

Add 6 to both sides to get 6x = 84, then divide both sides by 6 to get x = 14.

How do I check the answer?

Replace x by 14: 6(14) − 6 = 78, which is 78.

Solve 6x − 6 = 78

How to work it out

Trying values of x in 6x − 6 = 78

Questions

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