Express the following statements as equation of variation using k as constant

1. The variable m varies directly as the square of n.
2. The variable m varies inversely as the variablen.
3 The number of days, d, of work varies inversely as the number of workers, w
4. varies directly as the square of x and inversely as y.
5. Area (A) of a triangle varies jointly as its height(h) and length of the baserb).
Answer the following:
1.m varies directly as n, ifm-3 when n=2, find m when n = 3
2. y is directly proportional to x and y = 7 when x = 21, find the constant of variation
3. y varies jointly as x and y 9, when x 8, find y when x 12.
4. If y varies jointly as x and z, and when x = 4 and z = 5, find the constant of proportionality​