If a2+b2-4(a+b)= -8,then the value of (a-b) is:
A. 4 B. 0 C. 2 D. 8

• ans: 0
  
  a^2 + b^2 - 4(a+b) = -8
  a^2 + b^2 - 4a - 4b + 8 = 0
  (a^2 - 4a + 4) + (b^2 - 4b + 4) = 0
  (a - 2)^2 + (b - 2)^2 = 0
  
  So, the above condition is satisfy only when a=2 and b=2.
  Ans: a-b = 2 - 2
  = 0
• 6 years agoHelpfull: Yes(21) No(0)
• a^2 +b^2 -4(a+b)=-8
  or, a^2 -4a + 4 +b^2 -4b +4=0
  or, (a-2)^2+(b-2)^2=0
  implies both a=b=2 therefore (a-b)=0
• 6 years agoHelpfull: Yes(2) No(0)
• A. 4 i guess
• 6 years agoHelpfull: Yes(1) No(8)
• (a-2)^2 +(b-2)^2=0 then a=2
  b=2
  a-b=0
• 6 years agoHelpfull: Yes(1) No(0)
• Chandan Singha has given the perfect answer......
  By Hit and trail method also we can find the answer by putting both a=b=2;
• 6 years agoHelpfull: Yes(1) No(0)
• 2a+2b-4a-4b=-8
  -2a-2b=-8
  a-b=8
• 6 years agoHelpfull: Yes(0) No(10)