Solve 5x + 8 = −7

The solution of 5x + 8 = −7 is x = -3.

5x + 8 = -7\ \Rightarrow\ x = -3

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The lines y = 5x + 8 and y = -7 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 addition, then the multiplication.
$5x + 8 = -7$
2
Subtract 8 from both sides:
$5x + 8 - 8 = -7 - 8 \ \Rightarrow\ 5x = -15$
3
Divide both sides by 5:
$\frac{5x}{5} = \frac{-15}{5} \ \Rightarrow\ x = -3$
4
Check: put x = -3 back into the equation.
$5\cdot(-3) + 8 = -15 + 8 = -7 \checkmark$

LaTeX source of the formulas on this page

\[ 5x + 8 = -7\ \Rightarrow\ x = -3 \]
\[ 5x + 8 = -7 \]
\[ 5x + 8 - 8 = -7 - 8 \ \Rightarrow\ 5x = -15 \]
\[ \frac{5x}{5} = \frac{-15}{5} \ \Rightarrow\ x = -3 \]
\[ 5\cdot(-3) + 8 = -15 + 8 = -7 \checkmark \]

Trying values of x in 5x + 8 = −7

x	5x + 8	Equals -7?
-5	-17	no
-4	-12	no
-3	-7	yes
-2	-2	no
-1	3	no

Questions

What is x in 5x + 8 = −7?

The solution of 5x + 8 = −7 is x = -3.

How do you solve 5x + 8 = −7?

Subtract 8 from 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) + 8 = -7, which is -7.

Solve 5x + 8 = −7

How to work it out

Trying values of x in 5x + 8 = −7

Questions

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