Solve 7x − 5 = 72

The solution of 7x − 5 = 72 is x = 11.

7x - 5 = 72\ \Rightarrow\ x = 11

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The lines y = 7x − 5 and y = 72 meet at x = 11. 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.
$7x - 5 = 72$
2
Add 5 to both sides:
$7x - 5 + 5 = 72 + 5 \ \Rightarrow\ 7x = 77$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{77}{7} \ \Rightarrow\ x = 11$
4
Check: put x = 11 back into the equation.
$7\cdot11 - 5 = 77 - 5 = 72 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 5 = 72\ \Rightarrow\ x = 11 \]
\[ 7x - 5 = 72 \]
\[ 7x - 5 + 5 = 72 + 5 \ \Rightarrow\ 7x = 77 \]
\[ \frac{7x}{7} = \frac{77}{7} \ \Rightarrow\ x = 11 \]
\[ 7\cdot11 - 5 = 77 - 5 = 72 \checkmark \]

Trying values of x in 7x − 5 = 72

x	7x − 5	Equals 72?
9	58	no
10	65	no
11	72	yes
12	79	no
13	86	no

Questions

What is x in 7x − 5 = 72?

The solution of 7x − 5 = 72 is x = 11.

How do you solve 7x − 5 = 72?

Add 5 to both sides to get 7x = 77, then divide both sides by 7 to get x = 11.

How do I check the answer?

Replace x by 11: 7(11) − 5 = 72, which is 72.

Solve 7x − 5 = 72

How to work it out

Trying values of x in 7x − 5 = 72

Questions

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