Let r and s be the roots of 3x^2+4x-12=2x^2-6x+8. Find r^2 + s^2
Combine like terms: x^2 + 10x - 20
Manipulate: r^2 + s^2 = (r + s)^2 - 2rs
Vietas formula: r + s = -10, rs = -20
Substitution: (-10)^2 - 2(-20) = 100 + 40 = 140