±12
±3
±4
±6
Correct answer is A
The general form of a quadratic equation is:
\(x^2\)-(sum of roots) = 0
For equal roots it's:\(x^2 - 2(α)+(α)^2=0\)
\(3x^2+px+12=0\)
Divide through by 3
= \(x^2+\frac{p}{3}x+4=0\)
=\(x^2-(-\frac{p}{3})x+4=0\)
\(So,α^2=4\)
= α = √4 = ±2
Also,-\(\frac{p}{3}= 2α\)
When α = 2
-\(\frac{p}{3} = 2(2)=4\)
=p=-12
When α =-2
-\(\frac{p}{3}=2(-2)=-4\)
= p = 12
∴ values of p = ±12