+33661 Divide \(3x^2+4x-12=0\) by 3: \(x^2+\frac{4}{3}x-4=0\) ...(1)
Quadratic with roots r and s: \((x-r)(x-s)=0\) or \(x^2-(r+s)x+rs=0\) ...(2)
Compare (1) and (2) to see that \(r+s=-\frac{4}{3}\) ...(3)
Note that \(r^2 +s^2 + 2rs = (r+s)^2 \)
Now it should be easy to answer the question.
