let b be a positive integer and a=b^2-b. if b^3=4,then a^2-a is divisible by
a. 15
b. 20
c. 24
d. not

• not
  a^2-a=b^4-2b^3+b^2-b^2+b
  b^4-8+b
  4b-8+b
  5b-8
  b is +ve integer substiute any +ve integer we dont get any number divisible by above answers
  
• 11 years agoHelpfull: Yes(1) No(2)
• c)
  a^2-a=b^4-2b^3+b^2-b^2+b
  b^4-8+b
  4b-8+b
  5b-8
  substitute b=40
  and 192 is divisible by 24
• 11 years agoHelpfull: Yes(0) No(4)
• option d is correct
• 11 years agoHelpfull: Yes(0) No(1)
• d)
  a^2-a=b^4-2b^3+b^2-b^2+b
  b^4-8+b
  4b-8+b
  5b-8
  for different +ve values of b we get different answers which are not linked
• 11 years agoHelpfull: Yes(0) No(0)
• value of b is 64 n this no. r not diisible by any of answer
• 11 years agoHelpfull: Yes(0) No(0)