Solve 12x − 5 = 91

The solution of 12x − 5 = 91 is x = 8.

12x - 5 = 91\ \Rightarrow\ x = 8

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The lines y = 12x − 5 and y = 91 meet at x = 8. 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.
$12x - 5 = 91$
2
Add 5 to both sides:
$12x - 5 + 5 = 91 + 5 \ \Rightarrow\ 12x = 96$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{96}{12} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$12\cdot8 - 5 = 96 - 5 = 91 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 5 = 91\ \Rightarrow\ x = 8 \]
\[ 12x - 5 = 91 \]
\[ 12x - 5 + 5 = 91 + 5 \ \Rightarrow\ 12x = 96 \]
\[ \frac{12x}{12} = \frac{96}{12} \ \Rightarrow\ x = 8 \]
\[ 12\cdot8 - 5 = 96 - 5 = 91 \checkmark \]

Trying values of x in 12x − 5 = 91

x	12x − 5	Equals 91?
6	67	no
7	79	no
8	91	yes
9	103	no
10	115	no

Questions

What is x in 12x − 5 = 91?

The solution of 12x − 5 = 91 is x = 8.

How do you solve 12x − 5 = 91?

Add 5 to both sides to get 12x = 96, then divide both sides by 12 to get x = 8.

How do I check the answer?

Replace x by 8: 12(8) − 5 = 91, which is 91.

Solve 12x − 5 = 91

How to work it out

Trying values of x in 12x − 5 = 91

Questions

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