Select the expression that represents a rational function

Agrain trader buys the following amounts from three suppliers: 3,200 pounds, 5,100 pounds and 700 pounds. what is the total weight of his purchase?

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Which of the following equations is of the parabola whose vertex is at (4, 3), axis of symmetry parallel to the y-axis and focus at (4, -3)? a.) y+3=1/24 (x+4)^2 b.)y-3=-1/24 (x-4)^2 c.)x-4=-1/24 (y-3)^2