Solve 7x − 7 = 133

The solution of 7x − 7 = 133 is x = 20.

7x - 7 = 133\ \Rightarrow\ x = 20

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The lines y = 7x − 7 and y = 133 meet at x = 20. 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.
$7x - 7 = 133$
2
Add 7 to both sides:
$7x - 7 + 7 = 133 + 7 \ \Rightarrow\ 7x = 140$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{140}{7} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$7\cdot20 - 7 = 140 - 7 = 133 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 7 = 133\ \Rightarrow\ x = 20 \]
\[ 7x - 7 = 133 \]
\[ 7x - 7 + 7 = 133 + 7 \ \Rightarrow\ 7x = 140 \]
\[ \frac{7x}{7} = \frac{140}{7} \ \Rightarrow\ x = 20 \]
\[ 7\cdot20 - 7 = 140 - 7 = 133 \checkmark \]

Trying values of x in 7x − 7 = 133

x	7x − 7	Equals 133?
18	119	no
19	126	no
20	133	yes
21	140	no
22	147	no

Questions

What is x in 7x − 7 = 133?

The solution of 7x − 7 = 133 is x = 20.

How do you solve 7x − 7 = 133?

Add 7 to both sides to get 7x = 140, then divide both sides by 7 to get x = 20.

How do I check the answer?

Replace x by 20: 7(20) − 7 = 133, which is 133.

Solve 7x − 7 = 133

How to work it out

Trying values of x in 7x − 7 = 133

Questions

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