Question

How do you solve for x in `x+3(x+4)=20`?

Answer 1

See a solution process below:

Explanation:

First, expand the terms within parenthesis by multiplying each term within the parenthesis by the term outside the parenthesis:

`x + color(red)(3)(x + 4) = 20`

`x + (color(red)(3) * x) + (color(red)(3) * 4) = 20`

`x + 3x + 12 = 20`

`1x + 3x + 12 = 20`

`(1 + 3)x + 12 = 20`

`4x + 12 = 20`

Next, subtract `color(red)(12)` from each side of the equation to isolate the `x` term while keeping the equation balanced:

`4x + 12 - color(red)(12) = 20 - color(red)(12)`

`4x + 0 = 8`

`4x = 8`

Now, divide each side of the equation by `color(red)(4)` to solve for `x` while keeping the equation balanced:

`(4x)/color(red)(4) = 8/color(red)(4)`

`(color(red)(cancel(color(black)(4)))x)/cancel(color(red)(4)) = 2`

`x = 2`