(209*144)^2 + (209*209)+(209*144)+(144*144) = ?
a)905863729 b)905368729 c)905729368 d)65

• put x=209 and y=144
  so eqn becomes:(xy)^2+x^2+y^2+xy
  it can also be written as:(x+y)^2-xy+(xy)^2
  =(x+y)^2+xy(xy-1)
  =(353)^2+144*209(144*209-1)
  =905863729
• 14 years agoHelpfull: Yes(47) No(5)
• just do the operation (209*144)^2=905769216.Hence ans will be greater than this. Hence option c.
• 14 years agoHelpfull: Yes(30) No(28)
• put x=209 and y=144
  so eqn becomes:(xy)^2+x^2+y^2+xy
  therefore,(x+y)^2-xy+(xy)^2
  =(x+y)^2+xy(xy-1)
  =(353)^2+144*209(144*209-1)
  =905863729
• 14 years agoHelpfull: Yes(11) No(1)
• a)905863729
• 14 years agoHelpfull: Yes(3) No(4)
• put x=209 and y=144
  so eqn becomes:(xy)^2+x^2+y^2+xy
  therefore,(x+y)^2-xy+(xy)^2
  =(x+y)^2+xy(xy-1)
  =(353)^2+144*209(144*209-1)
  =905863729
• 9 years agoHelpfull: Yes(2) No(0)
• digit sum application
  (209*144)^2+(209*209)+(209*144)+(144*144)
  =(2*9)^2+(2*2)+(2*9)+(9*9)
  =(18)^2+(4)+(18)+(81)
  =(9)^2+(4)+(9)+(9)
  =(81)+4++9+9
  =9+4+4+9
  =31
  =4
  compare with no given no in option & number must be >(209*144)^2=905769216
• 9 years agoHelpfull: Yes(2) No(0)
• put x=209 y=144
  
  so en becomes (xy)^2+x^2+y^2+xy
  
  x^2+y^2-common
  (xy)^2+xy as it is
  
  so eqn becomes:(xy)^2+x^2+y^2+xy
  =(x+y)^2+xy(xy-1)
  =(353)^2+144*209(144*209-1)
  =905863729
  (x+y)^2-xy+(xy)^2
• 8 years agoHelpfull: Yes(0) No(0)
• put x=209 and y=144
  so eqn becomes:(xy)^2+x^2+y^2+xy
  it can also be written as:(x+y)^2-xy+(xy)^2
  =(x+y)^2+xy(xy-1)
  =(353)^2+144*209(144*209-1)
  =905863729
• 8 years agoHelpfull: Yes(0) No(0)