Question

How to use the discriminant to find out how many real number roots an equation has for `x^2=4`?

Answer 1

Write your equatiom as:
`x^2-4=0` which is in the form `ax^2+bx+c=0`
Where
`a=1`
`b=0`
`c=-4`
The discriminant `Delta` is:
`Delta=b^2-4ac==-4(1*-4)=16>0`
The fact that `Delta>0` tells you that your equation has 2 Real distinct solutions.

[`x_1=2` and `x_2=-2`]