Solve 5x − 15 = −45

The solution of 5x − 15 = −45 is x = -6.

5x - 15 = -45\ \Rightarrow\ x = -6

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The lines y = 5x − 15 and y = -45 meet at x = -6. 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.
$5x - 15 = -45$
2
Add 15 to both sides:
$5x - 15 + 15 = -45 + 15 \ \Rightarrow\ 5x = -30$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{-30}{5} \ \Rightarrow\ x = -6$
4
Check: put x = -6 back into the equation.
$5\cdot(-6) - 15 = -30 - 15 = -45 \checkmark$

LaTeX source of the formulas on this page

\[ 5x - 15 = -45\ \Rightarrow\ x = -6 \]
\[ 5x - 15 = -45 \]
\[ 5x - 15 + 15 = -45 + 15 \ \Rightarrow\ 5x = -30 \]
\[ \frac{5x}{5} = \frac{-30}{5} \ \Rightarrow\ x = -6 \]
\[ 5\cdot(-6) - 15 = -30 - 15 = -45 \checkmark \]

Trying values of x in 5x − 15 = −45

x	5x − 15	Equals -45?
-8	-55	no
-7	-50	no
-6	-45	yes
-5	-40	no
-4	-35	no

Questions

What is x in 5x − 15 = −45?

The solution of 5x − 15 = −45 is x = -6.

How do you solve 5x − 15 = −45?

Add 15 to both sides to get 5x = -30, then divide both sides by 5 to get x = -6.

How do I check the answer?

Replace x by -6: 5(-6) − 15 = -45, which is -45.

Solve 5x − 15 = −45

How to work it out

Trying values of x in 5x − 15 = −45

Questions

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