Hi

I have a quadratic -5x^2 + 15x +1 = 0

I can find x where y=0, (-54.1 or +24.1)

But how do I find x when y = 11

Factorising, completing the square and using the quadratic formula are

all about finding x when y = 0. But what do you do when you want y=

some other value?

Angus