Solve 12x − 3 = −99

The solution of 12x − 3 = −99 is x = -8.

12x - 3 = -99\ \Rightarrow\ x = -8

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The lines y = 12x − 3 and y = -99 meet at x = -8. 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.
$12x - 3 = -99$
2
Add 3 to both sides:
$12x - 3 + 3 = -99 + 3 \ \Rightarrow\ 12x = -96$
3
Divide both sides by 12:
$\frac{12x}{12} = \frac{-96}{12} \ \Rightarrow\ x = -8$
4
Check: put x = -8 back into the equation.
$12\cdot(-8) - 3 = -96 - 3 = -99 \checkmark$

LaTeX source of the formulas on this page

\[ 12x - 3 = -99\ \Rightarrow\ x = -8 \]
\[ 12x - 3 = -99 \]
\[ 12x - 3 + 3 = -99 + 3 \ \Rightarrow\ 12x = -96 \]
\[ \frac{12x}{12} = \frac{-96}{12} \ \Rightarrow\ x = -8 \]
\[ 12\cdot(-8) - 3 = -96 - 3 = -99 \checkmark \]

Trying values of x in 12x − 3 = −99

x	12x − 3	Equals -99?
-10	-123	no
-9	-111	no
-8	-99	yes
-7	-87	no
-6	-75	no

Questions

What is x in 12x − 3 = −99?

The solution of 12x − 3 = −99 is x = -8.

How do you solve 12x − 3 = −99?

Add 3 to both sides to get 12x = -96, then divide both sides by 12 to get x = -8.

How do I check the answer?

Replace x by -8: 12(-8) − 3 = -99, which is -99.

Solve 12x − 3 = −99

How to work it out

Trying values of x in 12x − 3 = −99

Questions

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