Solve 7x − 14 = 42

The solution of 7x − 14 = 42 is x = 8.

7x - 14 = 42\ \Rightarrow\ x = 8

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The lines y = 7x − 14 and y = 42 meet at x = 8. 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.
$7x - 14 = 42$
2
Add 14 to both sides:
$7x - 14 + 14 = 42 + 14 \ \Rightarrow\ 7x = 56$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{56}{7} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$7\cdot8 - 14 = 56 - 14 = 42 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 14 = 42\ \Rightarrow\ x = 8 \]
\[ 7x - 14 = 42 \]
\[ 7x - 14 + 14 = 42 + 14 \ \Rightarrow\ 7x = 56 \]
\[ \frac{7x}{7} = \frac{56}{7} \ \Rightarrow\ x = 8 \]
\[ 7\cdot8 - 14 = 56 - 14 = 42 \checkmark \]

Trying values of x in 7x − 14 = 42

x	7x − 14	Equals 42?
6	28	no
7	35	no
8	42	yes
9	49	no
10	56	no

Questions

What is x in 7x − 14 = 42?

The solution of 7x − 14 = 42 is x = 8.

How do you solve 7x − 14 = 42?

Add 14 to both sides to get 7x = 56, then divide both sides by 7 to get x = 8.

How do I check the answer?

Replace x by 8: 7(8) − 14 = 42, which is 42.

Solve 7x − 14 = 42

How to work it out

Trying values of x in 7x − 14 = 42

Questions

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