Answer:
C. 3x^2 + 2x + 1
Step-by-step explanation:
A. 12^2 - (4*3*12) = 0 (there's one solution.)
B. (-3)^2 - (4*3*-18) = 255 (there're 2 real solutions.)
D. 3^2 - (4*0*-3) = 9 (there're 2 real solutions.)
C. 2^2 - (4*3*1) = -18 ✅✅
if b^2 - 4ac = negative then we can say that there isn't any real solution for the equation.
