Solve 5x + 7 = −18

The solution of 5x + 7 = −18 is x = -5.

5x + 7 = -18\ \Rightarrow\ x = -5

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The lines y = 5x + 7 and y = -18 meet at x = -5. 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.
$5x + 7 = -18$
2
Subtract 7 from both sides:
$5x + 7 - 7 = -18 - 7 \ \Rightarrow\ 5x = -25$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{-25}{5} \ \Rightarrow\ x = -5$
4
Check: put x = -5 back into the equation.
$5\cdot(-5) + 7 = -25 + 7 = -18 \checkmark$

LaTeX source of the formulas on this page

\[ 5x + 7 = -18\ \Rightarrow\ x = -5 \]
\[ 5x + 7 = -18 \]
\[ 5x + 7 - 7 = -18 - 7 \ \Rightarrow\ 5x = -25 \]
\[ \frac{5x}{5} = \frac{-25}{5} \ \Rightarrow\ x = -5 \]
\[ 5\cdot(-5) + 7 = -25 + 7 = -18 \checkmark \]

Trying values of x in 5x + 7 = −18

x	5x + 7	Equals -18?
-7	-28	no
-6	-23	no
-5	-18	yes
-4	-13	no
-3	-8	no

Questions

What is x in 5x + 7 = −18?

The solution of 5x + 7 = −18 is x = -5.

How do you solve 5x + 7 = −18?

Subtract 7 from both sides to get 5x = -25, then divide both sides by 5 to get x = -5.

How do I check the answer?

Replace x by -5: 5(-5) + 7 = -18, which is -18.

Solve 5x + 7 = −18

How to work it out

Trying values of x in 5x + 7 = −18

Questions

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