Solve 8x − 15 = 17

The solution of 8x − 15 = 17 is x = 4.

8x - 15 = 17\ \Rightarrow\ x = 4

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The lines y = 8x − 15 and y = 17 meet at x = 4. 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.
$8x - 15 = 17$
2
Add 15 to both sides:
$8x - 15 + 15 = 17 + 15 \ \Rightarrow\ 8x = 32$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{32}{8} \ \Rightarrow\ x = 4$
4
Check: put x = 4 back into the equation.
$8\cdot4 - 15 = 32 - 15 = 17 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 15 = 17\ \Rightarrow\ x = 4 \]
\[ 8x - 15 = 17 \]
\[ 8x - 15 + 15 = 17 + 15 \ \Rightarrow\ 8x = 32 \]
\[ \frac{8x}{8} = \frac{32}{8} \ \Rightarrow\ x = 4 \]
\[ 8\cdot4 - 15 = 32 - 15 = 17 \checkmark \]

Trying values of x in 8x − 15 = 17

x	8x − 15	Equals 17?
2	1	no
3	9	no
4	17	yes
5	25	no
6	33	no

Questions

What is x in 8x − 15 = 17?

The solution of 8x − 15 = 17 is x = 4.

How do you solve 8x − 15 = 17?

Add 15 to both sides to get 8x = 32, then divide both sides by 8 to get x = 4.

How do I check the answer?

Replace x by 4: 8(4) − 15 = 17, which is 17.

Solve 8x − 15 = 17

How to work it out

Trying values of x in 8x − 15 = 17

Questions

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