Solve 8x + 8 = −40

The solution of 8x + 8 = −40 is x = -6.

8x + 8 = -40\ \Rightarrow\ x = -6

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The lines y = 8x + 8 and y = -40 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.
$8x + 8 = -40$
2
Subtract 8 from both sides:
$8x + 8 - 8 = -40 - 8 \ \Rightarrow\ 8x = -48$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{-48}{8} \ \Rightarrow\ x = -6$
4
Check: put x = -6 back into the equation.
$8\cdot(-6) + 8 = -48 + 8 = -40 \checkmark$

LaTeX source of the formulas on this page

\[ 8x + 8 = -40\ \Rightarrow\ x = -6 \]
\[ 8x + 8 = -40 \]
\[ 8x + 8 - 8 = -40 - 8 \ \Rightarrow\ 8x = -48 \]
\[ \frac{8x}{8} = \frac{-48}{8} \ \Rightarrow\ x = -6 \]
\[ 8\cdot(-6) + 8 = -48 + 8 = -40 \checkmark \]

Trying values of x in 8x + 8 = −40

x	8x + 8	Equals -40?
-8	-56	no
-7	-48	no
-6	-40	yes
-5	-32	no
-4	-24	no

Questions

What is x in 8x + 8 = −40?

The solution of 8x + 8 = −40 is x = -6.

How do you solve 8x + 8 = −40?

Subtract 8 from both sides to get 8x = -48, then divide both sides by 8 to get x = -6.

How do I check the answer?

Replace x by -6: 8(-6) + 8 = -40, which is -40.

Solve 8x + 8 = −40

How to work it out

Trying values of x in 8x + 8 = −40

Questions

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