The general form of a quadratic equation is:
x2-(sum of roots) = 0
For equal roots it's:x2−2(α)+(α)2=0
3x2+px+12=0
Divide through by 3
= x2+p3x+4=0
=x2−(−p3)x+4=0
So,α2=4
= α = √4 = ±2
Also,-p3=2α
When α = 2
-p3=2(2)=4
=p=-12
When α =-2
-p3=2(−2)=−4
= p = 12
∴ values of p = ±12