Solve 8x − 9 = 127

The solution of 8x − 9 = 127 is x = 17.

8x - 9 = 127\ \Rightarrow\ x = 17

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The lines y = 8x − 9 and y = 127 meet at x = 17. 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.
$8x - 9 = 127$
2
Add 9 to both sides:
$8x - 9 + 9 = 127 + 9 \ \Rightarrow\ 8x = 136$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{136}{8} \ \Rightarrow\ x = 17$
4
Check: put x = 17 back into the equation.
$8\cdot17 - 9 = 136 - 9 = 127 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 9 = 127\ \Rightarrow\ x = 17 \]
\[ 8x - 9 = 127 \]
\[ 8x - 9 + 9 = 127 + 9 \ \Rightarrow\ 8x = 136 \]
\[ \frac{8x}{8} = \frac{136}{8} \ \Rightarrow\ x = 17 \]
\[ 8\cdot17 - 9 = 136 - 9 = 127 \checkmark \]

Trying values of x in 8x − 9 = 127

x	8x − 9	Equals 127?
15	111	no
16	119	no
17	127	yes
18	135	no
19	143	no

Questions

What is x in 8x − 9 = 127?

The solution of 8x − 9 = 127 is x = 17.

How do you solve 8x − 9 = 127?

Add 9 to both sides to get 8x = 136, then divide both sides by 8 to get x = 17.

How do I check the answer?

Replace x by 17: 8(17) − 9 = 127, which is 127.

Solve 8x − 9 = 127

How to work it out

Trying values of x in 8x − 9 = 127

Questions

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