Question

15th, 16th and 17th on e please...

Answer 1

Answer of 17:

a^x-1=bc
b^y-1=ca
c^z-1=ac

a^x-1=bc => a^x / a = bc,
=>a^x = abc

b^y-1=ca => b^y / b = ca , =>b^y = abc

c^z-1=ac => c^z / c = ab ,
=>c^z = abc

a = (abc)^1/x

b = (abc)^1/y

c = (abc)^1/z

abc = (abc)^1/x+1/y+1/z

(abc)^1 = (abc)^1/x+1/y+1/z

1/x+1/y+1/z = 1

(xy + yz + zx) / xyz = 1

=> xy + yz + zx = xyz


Hope this helps