Solve 7x − 12 = 30

The solution of 7x − 12 = 30 is x = 6.

7x - 12 = 30\ \Rightarrow\ x = 6

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The lines y = 7x − 12 and y = 30 meet at x = 6. 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.
$7x - 12 = 30$
2
Add 12 to both sides:
$7x - 12 + 12 = 30 + 12 \ \Rightarrow\ 7x = 42$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{42}{7} \ \Rightarrow\ x = 6$
4
Check: put x = 6 back into the equation.
$7\cdot6 - 12 = 42 - 12 = 30 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 12 = 30\ \Rightarrow\ x = 6 \]
\[ 7x - 12 = 30 \]
\[ 7x - 12 + 12 = 30 + 12 \ \Rightarrow\ 7x = 42 \]
\[ \frac{7x}{7} = \frac{42}{7} \ \Rightarrow\ x = 6 \]
\[ 7\cdot6 - 12 = 42 - 12 = 30 \checkmark \]

Trying values of x in 7x − 12 = 30

x	7x − 12	Equals 30?
4	16	no
5	23	no
6	30	yes
7	37	no
8	44	no

Questions

What is x in 7x − 12 = 30?

The solution of 7x − 12 = 30 is x = 6.

How do you solve 7x − 12 = 30?

Add 12 to both sides to get 7x = 42, then divide both sides by 7 to get x = 6.

How do I check the answer?

Replace x by 6: 7(6) − 12 = 30, which is 30.

Solve 7x − 12 = 30

How to work it out

Trying values of x in 7x − 12 = 30

Questions

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