Solve 8x − 9 = 143

The solution of 8x − 9 = 143 is x = 19.

8x - 9 = 143\ \Rightarrow\ x = 19

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The lines y = 8x − 9 and y = 143 meet at x = 19. 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.
$8x - 9 = 143$
2
Add 9 to both sides:
$8x - 9 + 9 = 143 + 9 \ \Rightarrow\ 8x = 152$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{152}{8} \ \Rightarrow\ x = 19$
4
Check: put x = 19 back into the equation.
$8\cdot19 - 9 = 152 - 9 = 143 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 9 = 143\ \Rightarrow\ x = 19 \]
\[ 8x - 9 = 143 \]
\[ 8x - 9 + 9 = 143 + 9 \ \Rightarrow\ 8x = 152 \]
\[ \frac{8x}{8} = \frac{152}{8} \ \Rightarrow\ x = 19 \]
\[ 8\cdot19 - 9 = 152 - 9 = 143 \checkmark \]

Trying values of x in 8x − 9 = 143

x	8x − 9	Equals 143?
17	127	no
18	135	no
19	143	yes
20	151	no
21	159	no

Questions

What is x in 8x − 9 = 143?

The solution of 8x − 9 = 143 is x = 19.

How do you solve 8x − 9 = 143?

Add 9 to both sides to get 8x = 152, then divide both sides by 8 to get x = 19.

How do I check the answer?

Replace x by 19: 8(19) − 9 = 143, which is 143.

Solve 8x − 9 = 143

How to work it out

Trying values of x in 8x − 9 = 143

Questions

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