Question

2a=3+2b prove that 8a3-8b3-36ab=27

Answer 1

a-b= 3/2
(a-b)sq.= 9/4
now 8a3-8b3-36ab
=(2a)3-(2b)3-36ab
=(2a-2b)(4a2+4b2+4ab)-36ab
=3×4(a2+b2+ab)-36ab
=12a2+12b2+12ab-36ab
= 12a2+12b2-24ab
=12(a2+b2-2ab)
=12(a-b)2
=12×9/4
=3*9
=27 hence proven