Find the constant of variation for the relation and use it to write an equation for the statement. then solve the equation.
if y varies directly as x and z, and y =4 when x - 6 and z = 1, find y when x = 7 and z = 4
c. y = -xz; (7,4) -42
b. y - 12 v (7,4) - 2 -
d. y - xz; (7,4) –
select the best answer from the choices provided