Solve 8x + 9 = 73

The solution of 8x + 9 = 73 is x = 8.

8x + 9 = 73\ \Rightarrow\ x = 8

Explain it step by step in chat Make a short video of it

The lines y = 8x + 9 and y = 73 meet at x = 8. 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 addition, then the multiplication.
$8x + 9 = 73$
2
Subtract 9 from both sides:
$8x + 9 - 9 = 73 - 9 \ \Rightarrow\ 8x = 64$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{64}{8} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$8\cdot8 + 9 = 64 + 9 = 73 \checkmark$

LaTeX source of the formulas on this page

\[ 8x + 9 = 73\ \Rightarrow\ x = 8 \]
\[ 8x + 9 = 73 \]
\[ 8x + 9 - 9 = 73 - 9 \ \Rightarrow\ 8x = 64 \]
\[ \frac{8x}{8} = \frac{64}{8} \ \Rightarrow\ x = 8 \]
\[ 8\cdot8 + 9 = 64 + 9 = 73 \checkmark \]

Trying values of x in 8x + 9 = 73

x	8x + 9	Equals 73?
6	57	no
7	65	no
8	73	yes
9	81	no
10	89	no

Questions

What is x in 8x + 9 = 73?

The solution of 8x + 9 = 73 is x = 8.

How do you solve 8x + 9 = 73?

Subtract 9 from both sides to get 8x = 64, then divide both sides by 8 to get x = 8.

How do I check the answer?

Replace x by 8: 8(8) + 9 = 73, which is 73.

Solve 8x + 9 = 73

How to work it out

Trying values of x in 8x + 9 = 73

Questions

Similar equations