Solve 6x − 15 = 51

The solution of 6x − 15 = 51 is x = 11.

6x - 15 = 51\ \Rightarrow\ x = 11

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The lines y = 6x − 15 and y = 51 meet at x = 11. 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.
$6x - 15 = 51$
2
Add 15 to both sides:
$6x - 15 + 15 = 51 + 15 \ \Rightarrow\ 6x = 66$
3
Divide both sides by 6:
$\frac{6x}{6} = \frac{66}{6} \ \Rightarrow\ x = 11$
4
Check: put x = 11 back into the equation.
$6\cdot11 - 15 = 66 - 15 = 51 \checkmark$

LaTeX source of the formulas on this page

\[ 6x - 15 = 51\ \Rightarrow\ x = 11 \]
\[ 6x - 15 = 51 \]
\[ 6x - 15 + 15 = 51 + 15 \ \Rightarrow\ 6x = 66 \]
\[ \frac{6x}{6} = \frac{66}{6} \ \Rightarrow\ x = 11 \]
\[ 6\cdot11 - 15 = 66 - 15 = 51 \checkmark \]

Trying values of x in 6x − 15 = 51

x	6x − 15	Equals 51?
9	39	no
10	45	no
11	51	yes
12	57	no
13	63	no

Questions

What is x in 6x − 15 = 51?

The solution of 6x − 15 = 51 is x = 11.

How do you solve 6x − 15 = 51?

Add 15 to both sides to get 6x = 66, then divide both sides by 6 to get x = 11.

How do I check the answer?

Replace x by 11: 6(11) − 15 = 51, which is 51.

Solve 6x − 15 = 51

How to work it out

Trying values of x in 6x − 15 = 51

Questions

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