Question

How do you solve `5x + 4x + 7 = x + 15`?

Answer 1

Combine like terms and rearrange to solve for `x`. You will find that `x=1`

Explanation:

First, combine like terms on the Left Hand Side (LHS):

`5x+4x+7=x+15`

`x(5+4)+7=x+15`

`9x+7=x+15`

Next, we'll subtract 7 from both sides, which effectively moves the 7 to the Right Hand Side (RHS), and we will also subtract `x` from both sides, moving all `x`-related terms to the LHS:

`9xcancel(+7)color(red)(cancel(-7))color(blue)(-x)=cancel(x)+15color(red)(-7)color(blue)(cancel(-x))`

`9xcolor(blue)(-x)=15color(red)(-7)`

`8x=8`

Finally, divide both sides by `x`'s coefficient (8):

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

`color(green)(x=1`

Answer 2

`x=1`

Explanation:

`5x + 4x + 7 = x + 15`

`5x + 4x -x= 15 -7`

`8x = 8`

`x=1`