How do we solve quadratic equations by taking sqaure roots?

If b^2-4ac is a perfect square, then the 2 roots are rational. If b^2-4ac is not a perfect square, then the 2 roots are irrational.

For example , y= x^2+8x+10

Well first is first , D=b^2-4ac

So a= 1 , b=8 & c=10

Now substitute a , b & c in the formula : 8^2-4(1)(10) = 24 , 24 is > than 0 which means this has two solutions & since 24 is not a perfect square its irrational.