I think the answer is √20
let me know if I'm wrong. hope this helps
I think it might be r= -3
Answer is number 2
F(3)= (3-1)^2+ 3(3)=4+9= 13 so the first option is wrong
F(-2)= (-2-1)^2+ 3(-2)= 9-6=3 third options is wrong
F(-15)= (-15-1)^2 +3(-15)= 256-45= 211 fourth option is wrong
X is -10. I think, I might be wrong.