Suppose that the dependent variables z and w are functions of the independent variables x 5 and y, defined by the equations f(x, y, z, w) = 0 and g(x, y, z, w)

Suppose that the dependent variables z and w are functions of the independent variables x 5 and y, defined by the equations f(x, y, z, w) = 0 and g(x, y, z, w) = 0, where f9w -fw9z = 1. Which one of the following is correct? (a) z, = fugx - 9w (b) z, = f.9w- fu9 (c) z, =f9-19 (d) z, ,9w- 9