Solve 7x − 7 = 42

The solution of 7x − 7 = 42 is x = 7.

7x - 7 = 42\ \Rightarrow\ x = 7

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The lines y = 7x − 7 and y = 42 meet at x = 7. 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.
$7x - 7 = 42$
2
Add 7 to both sides:
$7x - 7 + 7 = 42 + 7 \ \Rightarrow\ 7x = 49$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{49}{7} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$7\cdot7 - 7 = 49 - 7 = 42 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 7 = 42\ \Rightarrow\ x = 7 \]
\[ 7x - 7 = 42 \]
\[ 7x - 7 + 7 = 42 + 7 \ \Rightarrow\ 7x = 49 \]
\[ \frac{7x}{7} = \frac{49}{7} \ \Rightarrow\ x = 7 \]
\[ 7\cdot7 - 7 = 49 - 7 = 42 \checkmark \]

Trying values of x in 7x − 7 = 42

x	7x − 7	Equals 42?
5	28	no
6	35	no
7	42	yes
8	49	no
9	56	no

Questions

What is x in 7x − 7 = 42?

The solution of 7x − 7 = 42 is x = 7.

How do you solve 7x − 7 = 42?

Add 7 to both sides to get 7x = 49, then divide both sides by 7 to get x = 7.

How do I check the answer?

Replace x by 7: 7(7) − 7 = 42, which is 42.

Solve 7x − 7 = 42

How to work it out

Trying values of x in 7x − 7 = 42

Questions

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