Solve 5x − 15 = 0

The solution of 5x − 15 = 0 is x = 3.

5x - 15 = 0\ \Rightarrow\ x = 3

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The lines y = 5x − 15 and y = 0 meet at x = 3. 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.
$5x - 15 = 0$
2
Add 15 to both sides:
$5x - 15 + 15 = 0 + 15 \ \Rightarrow\ 5x = 15$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{15}{5} \ \Rightarrow\ x = 3$
4
Check: put x = 3 back into the equation.
$5\cdot3 - 15 = 15 - 15 = 0 \checkmark$

LaTeX source of the formulas on this page

\[ 5x - 15 = 0\ \Rightarrow\ x = 3 \]
\[ 5x - 15 = 0 \]
\[ 5x - 15 + 15 = 0 + 15 \ \Rightarrow\ 5x = 15 \]
\[ \frac{5x}{5} = \frac{15}{5} \ \Rightarrow\ x = 3 \]
\[ 5\cdot3 - 15 = 15 - 15 = 0 \checkmark \]

Trying values of x in 5x − 15 = 0

x	5x − 15	Equals 0?
1	-10	no
2	-5	no
3	0	yes
4	5	no
5	10	no

Questions

What is x in 5x − 15 = 0?

The solution of 5x − 15 = 0 is x = 3.

How do you solve 5x − 15 = 0?

Add 15 to both sides to get 5x = 15, then divide both sides by 5 to get x = 3.

How do I check the answer?

Replace x by 3: 5(3) − 15 = 0, which is 0.

Solve 5x − 15 = 0

How to work it out

Trying values of x in 5x − 15 = 0

Questions

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