Question

What is the standard form of `y= (7/5x-4/7)^2+4`?

Answer 1

`y=49/25x^2 -8/5x + 212/49`

Explanation:

Basically you just expand out the bracket.

Rule for squaring things: the first squared, plus the last squared, plus twice the product of the two. (like if you had `(x+3)^2` it'd be `x^2 + 3^2 + "twice" (3*x) = x^2+6x+9`)

So, `(7/5x-4/7)^2` will be `(7/5x)^2` + `(-4/7)^2` + `2(7/5x*-4/7)`
`=49/25x^2 + 16/49 -8/5x`

Now add the +4:

`=49/25x^2 -8/5x + 4 + 16/49 = 49/25x^2 -8/5x +212/49`