Solve 8x − 1 = 15

The solution of 8x − 1 = 15 is x = 2.

8x - 1 = 15\ \Rightarrow\ x = 2

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The lines y = 8x − 1 and y = 15 meet at x = 2. 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.
$8x - 1 = 15$
2
Add 1 to both sides:
$8x - 1 + 1 = 15 + 1 \ \Rightarrow\ 8x = 16$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{16}{8} \ \Rightarrow\ x = 2$
4
Check: put x = 2 back into the equation.
$8\cdot2 - 1 = 16 - 1 = 15 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 1 = 15\ \Rightarrow\ x = 2 \]
\[ 8x - 1 = 15 \]
\[ 8x - 1 + 1 = 15 + 1 \ \Rightarrow\ 8x = 16 \]
\[ \frac{8x}{8} = \frac{16}{8} \ \Rightarrow\ x = 2 \]
\[ 8\cdot2 - 1 = 16 - 1 = 15 \checkmark \]

Trying values of x in 8x − 1 = 15

x	8x − 1	Equals 15?
0	-1	no
1	7	no
2	15	yes
3	23	no
4	31	no

Questions

What is x in 8x − 1 = 15?

The solution of 8x − 1 = 15 is x = 2.

How do you solve 8x − 1 = 15?

Add 1 to both sides to get 8x = 16, then divide both sides by 8 to get x = 2.

How do I check the answer?

Replace x by 2: 8(2) − 1 = 15, which is 15.

Solve 8x − 1 = 15

How to work it out

Trying values of x in 8x − 1 = 15

Questions

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