Solve 8x − 15 = 105

The solution of 8x − 15 = 105 is x = 15.

8x - 15 = 105\ \Rightarrow\ x = 15

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

The lines y = 8x − 15 and y = 105 meet at x = 15. 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.
$8x - 15 = 105$
2
Add 15 to both sides:
$8x - 15 + 15 = 105 + 15 \ \Rightarrow\ 8x = 120$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{120}{8} \ \Rightarrow\ x = 15$
4
Check: put x = 15 back into the equation.
$8\cdot15 - 15 = 120 - 15 = 105 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 15 = 105\ \Rightarrow\ x = 15 \]
\[ 8x - 15 = 105 \]
\[ 8x - 15 + 15 = 105 + 15 \ \Rightarrow\ 8x = 120 \]
\[ \frac{8x}{8} = \frac{120}{8} \ \Rightarrow\ x = 15 \]
\[ 8\cdot15 - 15 = 120 - 15 = 105 \checkmark \]

Trying values of x in 8x − 15 = 105

x	8x − 15	Equals 105?
13	89	no
14	97	no
15	105	yes
16	113	no
17	121	no

Questions

What is x in 8x − 15 = 105?

The solution of 8x − 15 = 105 is x = 15.

How do you solve 8x − 15 = 105?

Add 15 to both sides to get 8x = 120, then divide both sides by 8 to get x = 15.

How do I check the answer?

Replace x by 15: 8(15) − 15 = 105, which is 105.

Solve 8x − 15 = 105

How to work it out

Trying values of x in 8x − 15 = 105

Questions

Similar equations