Solve 8x − 9 = 103

The solution of 8x − 9 = 103 is x = 14.

8x - 9 = 103\ \Rightarrow\ x = 14

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The lines y = 8x − 9 and y = 103 meet at x = 14. 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.
$8x - 9 = 103$
2
Add 9 to both sides:
$8x - 9 + 9 = 103 + 9 \ \Rightarrow\ 8x = 112$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{112}{8} \ \Rightarrow\ x = 14$
4
Check: put x = 14 back into the equation.
$8\cdot14 - 9 = 112 - 9 = 103 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 9 = 103\ \Rightarrow\ x = 14 \]
\[ 8x - 9 = 103 \]
\[ 8x - 9 + 9 = 103 + 9 \ \Rightarrow\ 8x = 112 \]
\[ \frac{8x}{8} = \frac{112}{8} \ \Rightarrow\ x = 14 \]
\[ 8\cdot14 - 9 = 112 - 9 = 103 \checkmark \]

Trying values of x in 8x − 9 = 103

x	8x − 9	Equals 103?
12	87	no
13	95	no
14	103	yes
15	111	no
16	119	no

Questions

What is x in 8x − 9 = 103?

The solution of 8x − 9 = 103 is x = 14.

How do you solve 8x − 9 = 103?

Add 9 to both sides to get 8x = 112, then divide both sides by 8 to get x = 14.

How do I check the answer?

Replace x by 14: 8(14) − 9 = 103, which is 103.

Solve 8x − 9 = 103

How to work it out

Trying values of x in 8x − 9 = 103

Questions

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