Question

How do you solve `4( 3u + 9) > 9u + 15`?

Answer 1

`u\gt-7`

Explanation:

Simplify both sides, then solve for `u`

Distributive property on left end:
`4(3u+9)\gt9u+15`
`4(3u)+4(9)\gt9u+15`
`12u+36\gt9u+15`

Put any terms with `u` on the left side:
`12u\color(indianred)(-9u)+36\gt\cancel(9u)\cancel(\color(indianred)(-9u))+15`
`3u+36\gt15`
Take all other terms to the right side:
`3u\cancel(+36)\cancel(\color(steelblue)(-36))\gt15\color(steelblue)(-36)`
`3u\gt-21`

Simplify.
`(\cancel(3)u)/(\cancel(\color(seagreen)(3)))\gt-21/\color(seagreen)(3)`
`u\gt-7`

Source: Symbolab