Solve 7x − 7 = 28

The solution of 7x − 7 = 28 is x = 5.

7x - 7 = 28\ \Rightarrow\ x = 5

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The lines y = 7x − 7 and y = 28 meet at x = 5. 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.
$7x - 7 = 28$
2
Add 7 to both sides:
$7x - 7 + 7 = 28 + 7 \ \Rightarrow\ 7x = 35$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{35}{7} \ \Rightarrow\ x = 5$
4
Check: put x = 5 back into the equation.
$7\cdot5 - 7 = 35 - 7 = 28 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 7 = 28\ \Rightarrow\ x = 5 \]
\[ 7x - 7 = 28 \]
\[ 7x - 7 + 7 = 28 + 7 \ \Rightarrow\ 7x = 35 \]
\[ \frac{7x}{7} = \frac{35}{7} \ \Rightarrow\ x = 5 \]
\[ 7\cdot5 - 7 = 35 - 7 = 28 \checkmark \]

Trying values of x in 7x − 7 = 28

x	7x − 7	Equals 28?
3	14	no
4	21	no
5	28	yes
6	35	no
7	42	no

Questions

What is x in 7x − 7 = 28?

The solution of 7x − 7 = 28 is x = 5.

How do you solve 7x − 7 = 28?

Add 7 to both sides to get 7x = 35, then divide both sides by 7 to get x = 5.

How do I check the answer?

Replace x by 5: 7(5) − 7 = 28, which is 28.

Solve 7x − 7 = 28

How to work it out

Trying values of x in 7x − 7 = 28

Questions

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