Question

What is the standard form of `y=(2x+4)(x-5)`?

Answer 1

`y = 2x^2 - 6x - 20`

Explanation:

`y = (2x+4)(x-5)`

Standard quadratic form is `y = ax^2 + bx + c`.

Use FOIL to simplify:

Following this image, we can simplify/expand:
Firsts:
`2x * x = 2x^2`

Outers:
`2x * -5 = -10x`

Inners:
`4 * x = 4x`

Lasts:
`4 * -5 = -20`

Combine them all together:
`y = 2x^2 - 10x + 4x - 20`

Combine the like terms `-10x` and `4x`:
`y = 2x^2 - 6x - 20`

As you can see, this is in standard quadratic form `y = ax^2 + bx + c`

Hope this helps!