Solve 7x − 4 = 66

The solution of 7x − 4 = 66 is x = 10.

7x - 4 = 66\ \Rightarrow\ x = 10

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The lines y = 7x − 4 and y = 66 meet at x = 10. 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.
$7x - 4 = 66$
2
Add 4 to both sides:
$7x - 4 + 4 = 66 + 4 \ \Rightarrow\ 7x = 70$
3
Divide both sides by 7:
$\frac{7x}{7} = \frac{70}{7} \ \Rightarrow\ x = 10$
4
Check: put x = 10 back into the equation.
$7\cdot10 - 4 = 70 - 4 = 66 \checkmark$

LaTeX source of the formulas on this page

\[ 7x - 4 = 66\ \Rightarrow\ x = 10 \]
\[ 7x - 4 = 66 \]
\[ 7x - 4 + 4 = 66 + 4 \ \Rightarrow\ 7x = 70 \]
\[ \frac{7x}{7} = \frac{70}{7} \ \Rightarrow\ x = 10 \]
\[ 7\cdot10 - 4 = 70 - 4 = 66 \checkmark \]

Trying values of x in 7x − 4 = 66

x	7x − 4	Equals 66?
8	52	no
9	59	no
10	66	yes
11	73	no
12	80	no

Questions

What is x in 7x − 4 = 66?

The solution of 7x − 4 = 66 is x = 10.

How do you solve 7x − 4 = 66?

Add 4 to both sides to get 7x = 70, then divide both sides by 7 to get x = 10.

How do I check the answer?

Replace x by 10: 7(10) − 4 = 66, which is 66.

Solve 7x − 4 = 66

How to work it out

Trying values of x in 7x − 4 = 66

Questions

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