Determine the equation of joint variation. Then solve for the missing value.
x varies directly with y and z.
x = 400 when y = 8 and z = 10.
Find x when y = 10 and z = 12.
x varies directly with y and z.
x = 400 when y = 8 and z = 10.
Find x when y = 10 and z = 12.