Solve 6x − 9 = 39

The solution of 6x − 9 = 39 is x = 8.

6x - 9 = 39\ \Rightarrow\ x = 8

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The lines y = 6x − 9 and y = 39 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.
$6x - 9 = 39$
2
Add 9 to both sides:
$6x - 9 + 9 = 39 + 9 \ \Rightarrow\ 6x = 48$
3
Divide both sides by 6:
$\frac{6x}{6} = \frac{48}{6} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$6\cdot8 - 9 = 48 - 9 = 39 \checkmark$

LaTeX source of the formulas on this page

\[ 6x - 9 = 39\ \Rightarrow\ x = 8 \]
\[ 6x - 9 = 39 \]
\[ 6x - 9 + 9 = 39 + 9 \ \Rightarrow\ 6x = 48 \]
\[ \frac{6x}{6} = \frac{48}{6} \ \Rightarrow\ x = 8 \]
\[ 6\cdot8 - 9 = 48 - 9 = 39 \checkmark \]

Trying values of x in 6x − 9 = 39

x	6x − 9	Equals 39?
6	27	no
7	33	no
8	39	yes
9	45	no
10	51	no

Questions

What is x in 6x − 9 = 39?

The solution of 6x − 9 = 39 is x = 8.

How do you solve 6x − 9 = 39?

Add 9 to both sides to get 6x = 48, then divide both sides by 6 to get x = 8.

How do I check the answer?

Replace x by 8: 6(8) − 9 = 39, which is 39.

Solve 6x − 9 = 39

How to work it out

Trying values of x in 6x − 9 = 39

Questions

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