Question

Im working on factoring trinomials. Can anyone tell me how the factors of a quadratic equation can help you find the x intercepts?

Answer 1

x intercepts means where it crosses the x - axis. on the x axis the y value is 0. so it is the same as saying 'set your equation = 0 and solve'
if i have \[y=x^2-x-2\] and i want to know where it crosses the x - axis that is the same as saying solve for x:
\[x^2-x-2=0\]
now if i can factor this is easy:
\[x^2-x-2=0\]
\[(x-2)(x+1)=0\]
\[x=2\]or \[x=-1\] and therefore the x intercepts are 2 and -1
that is why i needed to factor, to find out where it is 0.