Solve 10x − 12 = −42

The solution of 10x − 12 = −42 is x = -3.

10x - 12 = -42\ \Rightarrow\ x = -3

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The lines y = 10x − 12 and y = -42 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 subtraction, then the multiplication.
$10x - 12 = -42$
2
Add 12 to both sides:
$10x - 12 + 12 = -42 + 12 \ \Rightarrow\ 10x = -30$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{-30}{10} \ \Rightarrow\ x = -3$
4
Check: put x = -3 back into the equation.
$10\cdot(-3) - 12 = -30 - 12 = -42 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 12 = -42\ \Rightarrow\ x = -3 \]
\[ 10x - 12 = -42 \]
\[ 10x - 12 + 12 = -42 + 12 \ \Rightarrow\ 10x = -30 \]
\[ \frac{10x}{10} = \frac{-30}{10} \ \Rightarrow\ x = -3 \]
\[ 10\cdot(-3) - 12 = -30 - 12 = -42 \checkmark \]

Trying values of x in 10x − 12 = −42

x	10x − 12	Equals -42?
-5	-62	no
-4	-52	no
-3	-42	yes
-2	-32	no
-1	-22	no

Questions

What is x in 10x − 12 = −42?

The solution of 10x − 12 = −42 is x = -3.

How do you solve 10x − 12 = −42?

Add 12 to both sides to get 10x = -30, then divide both sides by 10 to get x = -3.

How do I check the answer?

Replace x by -3: 10(-3) − 12 = -42, which is -42.

Solve 10x − 12 = −42

How to work it out

Trying values of x in 10x − 12 = −42

Questions

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