Solve 10x − 1 = 69

The solution of 10x − 1 = 69 is x = 7.

10x - 1 = 69\ \Rightarrow\ x = 7

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The lines y = 10x − 1 and y = 69 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.
$10x - 1 = 69$
2
Add 1 to both sides:
$10x - 1 + 1 = 69 + 1 \ \Rightarrow\ 10x = 70$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{70}{10} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$10\cdot7 - 1 = 70 - 1 = 69 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 1 = 69\ \Rightarrow\ x = 7 \]
\[ 10x - 1 = 69 \]
\[ 10x - 1 + 1 = 69 + 1 \ \Rightarrow\ 10x = 70 \]
\[ \frac{10x}{10} = \frac{70}{10} \ \Rightarrow\ x = 7 \]
\[ 10\cdot7 - 1 = 70 - 1 = 69 \checkmark \]

Trying values of x in 10x − 1 = 69

x	10x − 1	Equals 69?
5	49	no
6	59	no
7	69	yes
8	79	no
9	89	no

Questions

What is x in 10x − 1 = 69?

The solution of 10x − 1 = 69 is x = 7.

How do you solve 10x − 1 = 69?

Add 1 to both sides to get 10x = 70, then divide both sides by 10 to get x = 7.

How do I check the answer?

Replace x by 7: 10(7) − 1 = 69, which is 69.

Solve 10x − 1 = 69

How to work it out

Trying values of x in 10x − 1 = 69

Questions

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