Solve 5x − 8 = −18

The solution of 5x − 8 = −18 is x = -2.

5x - 8 = -18\ \Rightarrow\ x = -2

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The lines y = 5x − 8 and y = -18 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.
$5x - 8 = -18$
2
Add 8 to both sides:
$5x - 8 + 8 = -18 + 8 \ \Rightarrow\ 5x = -10$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{-10}{5} \ \Rightarrow\ x = -2$
4
Check: put x = -2 back into the equation.
$5\cdot(-2) - 8 = -10 - 8 = -18 \checkmark$

LaTeX source of the formulas on this page

\[ 5x - 8 = -18\ \Rightarrow\ x = -2 \]
\[ 5x - 8 = -18 \]
\[ 5x - 8 + 8 = -18 + 8 \ \Rightarrow\ 5x = -10 \]
\[ \frac{5x}{5} = \frac{-10}{5} \ \Rightarrow\ x = -2 \]
\[ 5\cdot(-2) - 8 = -10 - 8 = -18 \checkmark \]

Trying values of x in 5x − 8 = −18

x	5x − 8	Equals -18?
-4	-28	no
-3	-23	no
-2	-18	yes
-1	-13	no
0	-8	no

Questions

What is x in 5x − 8 = −18?

The solution of 5x − 8 = −18 is x = -2.

How do you solve 5x − 8 = −18?

Add 8 to both sides to get 5x = -10, then divide both sides by 5 to get x = -2.

How do I check the answer?

Replace x by -2: 5(-2) − 8 = -18, which is -18.

Solve 5x − 8 = −18

How to work it out

Trying values of x in 5x − 8 = −18

Questions

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