Need with a-d in the pic below! in advance

125 grew only wheat
106 grew onlycorn
91   grew onlyoats
198 grew wheat
58  grew wheat and corn
49  grew wheat and oats
172 grew corn

we have 
corn
106 grew onlycorn
172 grew corn
58  grew wheat and corn
172-106=66 wheat corn and oats
58  grew wheat and corn
66-58=8corn and oats
remains
106 grew onlycorn
172 grew 106 corn +58 wheat and corn + 8 corn and oats

oats
91   grew onlyoats
49  grew wheat and oats

wheat
125 grew only wheat
198 grew wheat
58  grew wheat and corn
49  grew wheat and oats
198-125=73  wheat, corn and oats

answers
a) Number of farmers who grew at least one of the three
125+106+91=322 farmers

b) Number of farmers who grew all three
66+73=139 farmers

c) Number of farmers who did not grow any of the three
322+58+8+49=437 farmers

d) Number of farmers who grew exactly two of the three
58+8+49=115 farmers

8y+7= y+21
Subtract y from both side
7y+7=21
Subtract 7 from both sides
7y = 14
Divide both sides by 7
Y=2 or A