Can someone help me solve this problem

The problem is:
Solve the linear programming problem by the method of corners.
Minimize C = 4x + 6y
subject to these constraints
4x + y ≥36
2x + y≥30
x+ 3y≥30
x ≥ 0, y ≥ 0

I have tried everything and can't figure out what I'm doing wrong. Any help?

if you sketch these properly you should see that the corner points of the region are

( 30 , 0 ) , ( 12 , 6 ) , (0,36) , & ( 3 , 24 ) , with the min at the 2nd point