Solve 2x − 9 = 7

The solution of 2x − 9 = 7 is x = 8.

2x - 9 = 7\ \Rightarrow\ x = 8

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The lines y = 2x − 9 and y = 7 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.
$2x - 9 = 7$
2
Add 9 to both sides:
$2x - 9 + 9 = 7 + 9 \ \Rightarrow\ 2x = 16$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{16}{2} \ \Rightarrow\ x = 8$
4
Check: put x = 8 back into the equation.
$2\cdot8 - 9 = 16 - 9 = 7 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 9 = 7\ \Rightarrow\ x = 8 \]
\[ 2x - 9 = 7 \]
\[ 2x - 9 + 9 = 7 + 9 \ \Rightarrow\ 2x = 16 \]
\[ \frac{2x}{2} = \frac{16}{2} \ \Rightarrow\ x = 8 \]
\[ 2\cdot8 - 9 = 16 - 9 = 7 \checkmark \]

Trying values of x in 2x − 9 = 7

x	2x − 9	Equals 7?
6	3	no
7	5	no
8	7	yes
9	9	no
10	11	no

Questions

What is x in 2x − 9 = 7?

The solution of 2x − 9 = 7 is x = 8.

How do you solve 2x − 9 = 7?

Add 9 to both sides to get 2x = 16, then divide both sides by 2 to get x = 8.

How do I check the answer?

Replace x by 8: 2(8) − 9 = 7, which is 7.

Solve 2x − 9 = 7

How to work it out

Trying values of x in 2x − 9 = 7

Questions

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