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

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Answer 1 · 2015-07-27T10:59:50

Isolate $x$ on one side of the equation.

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.

How do you solve 2x + 1 = 92x + 1 = 9?