Question

How do you solve `2x + 1 = 9`?

Answer 1

Isolate `x` on one side of the equation.

Explanation:

In order to solve this equation, you have to isolate`x` on one side of the equation. You can do that in two steps.

First, add `-1` to both sides of the equation

`2x + color(red)(cancel(color(black)(1))) - color(red)(cancel(color(black)(1))) = 9 - 1`

`2x = 8`

Finally, divide both sides of the equation by `2` to get

`(color(red)(cancel(color(black)(2))) * x)/color(red)(cancel(color(black)(2))) = 8/2`

`x = color(green)(4)`

And there you have it. If you double `x` and add one, you get nine.