Ok i have two similar questions. the first one is if you have a quadratic how do you find the x-intercepts. ex. y=-x^2+8x-5 (i know how to do ones where you can look on the graph but i can't figure out the ones that aren't whole numbers)

Question

anonymous · Answer

Either factorise the quadratic or use the quadratic eqn 

-b+sqrt(b^2-4ac))
-----------------   etc
         2a 

this give the points where it crosses the x axis and y=0

anonymous · Answer

use b^2-4ac to see if it has real roots or a single root or imaginary roots
above is >0 2 real roots
above =0 1 real root
above < 0 imaginary roots

anonymous · Answer

Oh right i forgot that formula... but that only gives me one of them right... i have to subtract the square root to get the other one right? and for roots... i have no idea what you're talking about i'm sorry

anonymous · Answer

yes the formula is  -b plus or minus so you do it twice one for each

anonymous · Answer

ok thank you...

anonymous · Answer

np