Which relationship among ( x(1),x(2) ) and ( x(3) ), is invalid for the multiple regression model ( y=A+B(1)x(1)+B(2)x(2)+B(3)x(3)+ϵ )?
a. ( x(1)=x(3)⁴ )
b. ( x(1)=7x(2)+4x(3) )
c. ( x(3)=x(2)²-3x(3) )
d. ( x(2) )