Solve 3x − 6 = 42

The solution of 3x − 6 = 42 is x = 16.

3x - 6 = 42\ \Rightarrow\ x = 16

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The lines y = 3x − 6 and y = 42 meet at x = 16. 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.
$3x - 6 = 42$
2
Add 6 to both sides:
$3x - 6 + 6 = 42 + 6 \ \Rightarrow\ 3x = 48$
3
Divide both sides by 3:
$\frac{3x}{3} = \frac{48}{3} \ \Rightarrow\ x = 16$
4
Check: put x = 16 back into the equation.
$3\cdot16 - 6 = 48 - 6 = 42 \checkmark$

LaTeX source of the formulas on this page

\[ 3x - 6 = 42\ \Rightarrow\ x = 16 \]
\[ 3x - 6 = 42 \]
\[ 3x - 6 + 6 = 42 + 6 \ \Rightarrow\ 3x = 48 \]
\[ \frac{3x}{3} = \frac{48}{3} \ \Rightarrow\ x = 16 \]
\[ 3\cdot16 - 6 = 48 - 6 = 42 \checkmark \]

Trying values of x in 3x − 6 = 42

x	3x − 6	Equals 42?
14	36	no
15	39	no
16	42	yes
17	45	no
18	48	no

Questions

What is x in 3x − 6 = 42?

The solution of 3x − 6 = 42 is x = 16.

How do you solve 3x − 6 = 42?

Add 6 to both sides to get 3x = 48, then divide both sides by 3 to get x = 16.

How do I check the answer?

Replace x by 16: 3(16) − 6 = 42, which is 42.

Solve 3x − 6 = 42

How to work it out

Trying values of x in 3x − 6 = 42

Questions

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