Solve 7x − 5 = 135

The solution of 7x − 5 = 135 is x = 20.

7x - 5 = 135\ \Rightarrow\ x = 20

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The lines y = 7x − 5 and y = 135 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.
$7x - 5 = 135$
2
Add 5 to both sides:
$7x - 5 + 5 = 135 + 5 \ \Rightarrow\ 7x = 140$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{140}{7} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$7\cdot20 - 5 = 140 - 5 = 135 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 5 = 135\ \Rightarrow\ x = 20 \]
\[ 7x - 5 = 135 \]
\[ 7x - 5 + 5 = 135 + 5 \ \Rightarrow\ 7x = 140 \]
\[ \frac{7x}{7} = \frac{140}{7} \ \Rightarrow\ x = 20 \]
\[ 7\cdot20 - 5 = 140 - 5 = 135 \checkmark \]

Trying values of x in 7x − 5 = 135

x	7x − 5	Equals 135?
18	121	no
19	128	no
20	135	yes
21	142	no
22	149	no

Questions

What is x in 7x − 5 = 135?

The solution of 7x − 5 = 135 is x = 20.

How do you solve 7x − 5 = 135?

Add 5 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) − 5 = 135, which is 135.

Solve 7x − 5 = 135

How to work it out

Trying values of x in 7x − 5 = 135

Questions

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