Solve 2x + 1 = 15

The solution of 2x + 1 = 15 is x = 7.

2x + 1 = 15\ \Rightarrow\ x = 7

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The lines y = 2x + 1 and y = 15 meet at x = 7. 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 addition, then the multiplication.
$2x + 1 = 15$
2
Subtract 1 from both sides:
$2x + 1 - 1 = 15 - 1 \ \Rightarrow\ 2x = 14$
3
Divide both sides by 2:
$\frac{2x}{2} = \frac{14}{2} \ \Rightarrow\ x = 7$
4
Check: put x = 7 back into the equation.
$2\cdot7 + 1 = 14 + 1 = 15 \checkmark$

LaTeX source of the formulas on this page

\[ 2x + 1 = 15\ \Rightarrow\ x = 7 \]
\[ 2x + 1 = 15 \]
\[ 2x + 1 - 1 = 15 - 1 \ \Rightarrow\ 2x = 14 \]
\[ \frac{2x}{2} = \frac{14}{2} \ \Rightarrow\ x = 7 \]
\[ 2\cdot7 + 1 = 14 + 1 = 15 \checkmark \]

Trying values of x in 2x + 1 = 15

x	2x + 1	Equals 15?
5	11	no
6	13	no
7	15	yes
8	17	no
9	19	no

Questions

What is x in 2x + 1 = 15?

The solution of 2x + 1 = 15 is x = 7.

How do you solve 2x + 1 = 15?

Subtract 1 from both sides to get 2x = 14, then divide both sides by 2 to get x = 7.

How do I check the answer?

Replace x by 7: 2(7) + 1 = 15, which is 15.

Solve 2x + 1 = 15

How to work it out

Trying values of x in 2x + 1 = 15

Questions

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