Answer:
k=0
Step-by-step explanation:
R(x)=kx-2x²
R(1/4)=k(1/4)-2(1/4)²=k/4-1/8
R(-1/4)=k(-1/4)-2(-1/4)²=-k/4-1/8
R(1/4)=R(-1/4)
k/4-1/8=-k/4-1/8
k/4+k/4=1/8-1/8
2k/4=0
2k=0
