Solve 10x − 9 = 51

The solution of 10x − 9 = 51 is x = 6.

10x - 9 = 51\ \Rightarrow\ x = 6

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The lines y = 10x − 9 and y = 51 meet at x = 6. 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.
$10x - 9 = 51$
2
Add 9 to both sides:
$10x - 9 + 9 = 51 + 9 \ \Rightarrow\ 10x = 60$
3
Divide both sides by 10:
$\frac{10x}{10} = \frac{60}{10} \ \Rightarrow\ x = 6$
4
Check: put x = 6 back into the equation.
$10\cdot6 - 9 = 60 - 9 = 51 \checkmark$

LaTeX source of the formulas on this page

\[ 10x - 9 = 51\ \Rightarrow\ x = 6 \]
\[ 10x - 9 = 51 \]
\[ 10x - 9 + 9 = 51 + 9 \ \Rightarrow\ 10x = 60 \]
\[ \frac{10x}{10} = \frac{60}{10} \ \Rightarrow\ x = 6 \]
\[ 10\cdot6 - 9 = 60 - 9 = 51 \checkmark \]

Trying values of x in 10x − 9 = 51

x	10x − 9	Equals 51?
4	31	no
5	41	no
6	51	yes
7	61	no
8	71	no

Questions

What is x in 10x − 9 = 51?

The solution of 10x − 9 = 51 is x = 6.

How do you solve 10x − 9 = 51?

Add 9 to both sides to get 10x = 60, then divide both sides by 10 to get x = 6.

How do I check the answer?

Replace x by 6: 10(6) − 9 = 51, which is 51.

Solve 10x − 9 = 51

How to work it out

Trying values of x in 10x − 9 = 51

Questions

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