Question

What is `b` in this quadratic equation `3x^2 - 15 = 8x`?

Answer 1

`b=-8`

Explanation:

Given: `3x^2-15=8x`

Subtract `8x` from both sides.

`3x^2color(white)(".")color(red)(-8)x-15=0`
`ax^2color(white)(".")ubrace(+color(red)(b))x+color(white)("d")c=0`
`color(white)(".d..d")darr`
`color(white)("dd")obrace(+(color(red)(-8)))color(white)("d")->-8`