Solve 8x − 13 = −69

The solution of 8x − 13 = −69 is x = -7.

8x - 13 = -69\ \Rightarrow\ x = -7

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The lines y = 8x − 13 and y = -69 meet at x = -7. 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.
$8x - 13 = -69$
2
Add 13 to both sides:
$8x - 13 + 13 = -69 + 13 \ \Rightarrow\ 8x = -56$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{-56}{8} \ \Rightarrow\ x = -7$
4
Check: put x = -7 back into the equation.
$8\cdot(-7) - 13 = -56 - 13 = -69 \checkmark$

LaTeX source of the formulas on this page

\[ 8x - 13 = -69\ \Rightarrow\ x = -7 \]
\[ 8x - 13 = -69 \]
\[ 8x - 13 + 13 = -69 + 13 \ \Rightarrow\ 8x = -56 \]
\[ \frac{8x}{8} = \frac{-56}{8} \ \Rightarrow\ x = -7 \]
\[ 8\cdot(-7) - 13 = -56 - 13 = -69 \checkmark \]

Trying values of x in 8x − 13 = −69

x	8x − 13	Equals -69?
-9	-85	no
-8	-77	no
-7	-69	yes
-6	-61	no
-5	-53	no

Questions

What is x in 8x − 13 = −69?

The solution of 8x − 13 = −69 is x = -7.

How do you solve 8x − 13 = −69?

Add 13 to both sides to get 8x = -56, then divide both sides by 8 to get x = -7.

How do I check the answer?

Replace x by -7: 8(-7) − 13 = -69, which is -69.

Solve 8x − 13 = −69

How to work it out

Trying values of x in 8x − 13 = −69

Questions

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