.I did not come here for quick answers. I've just been trying this for a long time to no avail. Help would be much appreciated.

Write the expression 3x^24 + 4x^ 12 + 7 in quadratic form.

A: 3x^24 + 4x^12 + 7 ?

let u = x^12 ...

3u^2 + 4u + 7

Write the expression-5x^4 - 10x + 6in quadratic form.

is it supposed to be-5x^4 - 10x^2 + 6 ??