Show that the equation `x^2+a x-4=0` has real and distinct roots for all real values of `a` .

Explanation

The given equation is `x^(2)-ax-4=0.`
This is of the form `Ax^(2)+Bx+C=0,` where A=1, B=a and C=-4.
`:." "D=(B^(2)-4AC)={a^(2)-4xx1xx(-4)}=(a^(2)+16)bt0` fro all real values of a.
Thus, `Dgt0` for all real values of a.
Hence, the given equation has real and distinct roots for all real values of a.