I don't usually have any problem with simultaneous equations but whilst revising for a test, I came across two types that I haven't seen before and the book I have only gives answers but no explanations of how it got those answers. I've tried in various ways... but my answers never seem to match up.

Could anyone solve these two simultaneous equations step-by-step so I could see how it's done?

Q1)

$\displaystyle y = 1 - 4x$

$\displaystyle y = -4x^2$

Q2)

$\displaystyle xy = 9$

$\displaystyle x - 2y = 3$

If anyone could I would really appreciate it, thanks. And Hi to everyone on the forum - just found this forum and it looks great.