Solve 5x + 15 = −15

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

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

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The lines y = 5x + 15 and y = -15 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 addition, then the multiplication.
$5x + 15 = -15$
2
Subtract 15 from both sides:
$5x + 15 - 15 = -15 - 15 \ \Rightarrow\ 5x = -30$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{-30}{5} \ \Rightarrow\ x = -6$
4
Check: put x = -6 back into the equation.
$5\cdot(-6) + 15 = -30 + 15 = -15 \checkmark$

LaTeX source of the formulas on this page

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

Trying values of x in 5x + 15 = −15

x	5x + 15	Equals -15?
-8	-25	no
-7	-20	no
-6	-15	yes
-5	-10	no
-4	-5	no

Questions

What is x in 5x + 15 = −15?

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

How do you solve 5x + 15 = −15?

Subtract 15 from 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 = -15, which is -15.

Solve 5x + 15 = −15

How to work it out

Trying values of x in 5x + 15 = −15

Questions

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