Solve 8x + 12 = −28

The solution of 8x + 12 = −28 is x = -5.

8x + 12 = -28\ \Rightarrow\ x = -5

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The lines y = 8x + 12 and y = -28 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.
$8x + 12 = -28$
2
Subtract 12 from both sides:
$8x + 12 - 12 = -28 - 12 \ \Rightarrow\ 8x = -40$
3
Divide both sides by 8:
$\frac{8x}{8} = \frac{-40}{8} \ \Rightarrow\ x = -5$
4
Check: put x = -5 back into the equation.
$8\cdot(-5) + 12 = -40 + 12 = -28 \checkmark$

LaTeX source of the formulas on this page

\[ 8x + 12 = -28\ \Rightarrow\ x = -5 \]
\[ 8x + 12 = -28 \]
\[ 8x + 12 - 12 = -28 - 12 \ \Rightarrow\ 8x = -40 \]
\[ \frac{8x}{8} = \frac{-40}{8} \ \Rightarrow\ x = -5 \]
\[ 8\cdot(-5) + 12 = -40 + 12 = -28 \checkmark \]

Trying values of x in 8x + 12 = −28

x	8x + 12	Equals -28?
-7	-44	no
-6	-36	no
-5	-28	yes
-4	-20	no
-3	-12	no

Questions

What is x in 8x + 12 = −28?

The solution of 8x + 12 = −28 is x = -5.

How do you solve 8x + 12 = −28?

Subtract 12 from both sides to get 8x = -40, then divide both sides by 8 to get x = -5.

How do I check the answer?

Replace x by -5: 8(-5) + 12 = -28, which is -28.

Solve 8x + 12 = −28

How to work it out

Trying values of x in 8x + 12 = −28

Questions

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