Solve 2x − 1 = 39

The solution of 2x − 1 = 39 is x = 20.

2x - 1 = 39\ \Rightarrow\ x = 20

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The lines y = 2x − 1 and y = 39 meet at x = 20. 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.
$2x - 1 = 39$
2
Add 1 to both sides:
$2x - 1 + 1 = 39 + 1 \ \Rightarrow\ 2x = 40$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{40}{2} \ \Rightarrow\ x = 20$
4
Check: put x = 20 back into the equation.
$2\cdot20 - 1 = 40 - 1 = 39 \checkmark$

LaTeX source of the formulas on this page

\[ 2x - 1 = 39\ \Rightarrow\ x = 20 \]
\[ 2x - 1 = 39 \]
\[ 2x - 1 + 1 = 39 + 1 \ \Rightarrow\ 2x = 40 \]
\[ \frac{2x}{2} = \frac{40}{2} \ \Rightarrow\ x = 20 \]
\[ 2\cdot20 - 1 = 40 - 1 = 39 \checkmark \]

Trying values of x in 2x − 1 = 39

x	2x − 1	Equals 39?
18	35	no
19	37	no
20	39	yes
21	41	no
22	43	no

Questions

What is x in 2x − 1 = 39?

The solution of 2x − 1 = 39 is x = 20.

How do you solve 2x − 1 = 39?

Add 1 to both sides to get 2x = 40, then divide both sides by 2 to get x = 20.

How do I check the answer?

Replace x by 20: 2(20) − 1 = 39, which is 39.

Solve 2x − 1 = 39

How to work it out

Trying values of x in 2x − 1 = 39

Questions

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