Question

if a²-b²=9 and ab=20 prove that a³+b³=189

Answer 1

a=5 & b=4
so how to find always check to adjacent numbers
so 1*1*1-2*2*2= no 9
and so on
son lets check 4&5
they are adj. to
5*5-4*4=9
25-16=9
so a=5 &b=4
ab=20
5*4=20
5*5*5+4*4*4=189
125+64=189
so a=5 &b=4