Solve 8x − 1 = 143

The solution of 8x − 1 = 143 is x = 18.

8x - 1 = 143\ \Rightarrow\ x = 18

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The lines y = 8x − 1 and y = 143 meet at x = 18. 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.
$8x - 1 = 143$
2
Add 1 to both sides:
$8x - 1 + 1 = 143 + 1 \ \Rightarrow\ 8x = 144$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{144}{8} \ \Rightarrow\ x = 18$
4
Check: put x = 18 back into the equation.
$8\cdot18 - 1 = 144 - 1 = 143 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 1 = 143\ \Rightarrow\ x = 18 \]
\[ 8x - 1 = 143 \]
\[ 8x - 1 + 1 = 143 + 1 \ \Rightarrow\ 8x = 144 \]
\[ \frac{8x}{8} = \frac{144}{8} \ \Rightarrow\ x = 18 \]
\[ 8\cdot18 - 1 = 144 - 1 = 143 \checkmark \]

Trying values of x in 8x − 1 = 143

x	8x − 1	Equals 143?
16	127	no
17	135	no
18	143	yes
19	151	no
20	159	no

Questions

What is x in 8x − 1 = 143?

The solution of 8x − 1 = 143 is x = 18.

How do you solve 8x − 1 = 143?

Add 1 to both sides to get 8x = 144, then divide both sides by 8 to get x = 18.

How do I check the answer?

Replace x by 18: 8(18) − 1 = 143, which is 143.

Solve 8x − 1 = 143

How to work it out

Trying values of x in 8x − 1 = 143

Questions

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