Aim: How do we solve quadratic equations by taking square roots?

If b^2-4ac is a perfect square, then the two roots are rational.
If b^2-4ac isn't a perfect square, then the two roots are irrational.
Examples:

y=x^2+6x+8

a= x^2
b=6
c=8
b^2-4ac= 6^2-4(1)(8)
36-4(8)
36-32=4
Rational b/c 4 is a perfect square

y=x^2=3x-1
a=1
b=3
c=-1
b^2-4ac= 3^2-4(1)(-1)
9-4(-1)
9+4=13
Irrational b/c 13 isn't a perfect square