If f(1)=4 and f(x+y)=f(x)+f(y)+7xy+4, then f(2)+f(5)=?

• f(1)=4
  f(1+1)=19
  f(1+2)=48
  f(2+2)=70
  f(2+3)=106
  
  then f(2)+f(5)=125
  
• 11 years agoHelpfull: Yes(23) No(12)
• 125 ans
  f(2)=f(1)+f(1)+7*1*1+4=4+4+7+4=19
  f(3)=f(1)+f(2)+7*1*2+4=4+19+18=41
  f(5)=f(2)+f(3)+7*2*3+4=19+41+46=106
  106+19=125
• 11 years agoHelpfull: Yes(12) No(0)
• f(2)=f(1)+f(1)+7*1*1+4=19
  f(5)=f(2)+f(3)+7*2*3+4
  =19+[f(2)+f(1)+7*2*1+4]+7*2*3+4
  =19+19+4+14+4+42+4
  =106
• 11 years agoHelpfull: Yes(8) No(12)
• f(2+5)=f(2)+f(5)+7(2)(5)+4
  =>f(2)+f(5)=f(7)-70-4=>f(7)-74
  =>f(1)=4
  f(1+1)=19
  f(2+1)=41
  f(2+2)=70
  so f(7)=f(3+4)=199
  f(2)+f(5)=199-74
  i.e., 125
• 11 years agoHelpfull: Yes(8) No(0)
• f(1)=4 is given,
  f(x+y)=f(x)+f(y)+7xy+4
  then take to the x=1 and y=1
  f(2)=f(1)+f(1)+7(1)(1)+4
  =4+4+7+4
  f(2)=19.
  after find f(3)=f(1)+f(2)+7(1)(2)+4
  =4+19+14+4
  =41.
  NEXT f(5), take to the x value = 3 and y value = 2
  f(5)=f(3)+f(2)+7(3)(2)+4
  =41+19+42+4
  =106.
  add f(2)+f(5)=19+106
  ans is =125.
• 11 years agoHelpfull: Yes(3) No(0)
• f(1)=4
  f(2)=>f(1+1)=f(1)+f(1)+7(1)(1)+4=>4+4+7+4
  =>19
  f(3)=>f(1+2)=f(1)+f(2)+7(1)(2)+4=>4+19+14+4
  =>41
  f(5)=>f(2+3)=f(2)+f(3)+7(2)(3)+4=>19+41+42+4
  =>106
  f(2)+f(5)=19+106
  =125 answer
• 11 years agoHelpfull: Yes(2) No(0)
• f(2)=f(1)+f(1)+7*1*1+4
  =4+4+7+4=19
  f(2)=19
  f(2+1)=f(2)+f(1)+7*2*1+4
  =19+4+14+4
  f(3)=41
  f(3+2)=f(3)+f(2)+7*3*2+4
  =41+19+42+4
  =106
  f(2)+f(5)=19+106=125
  
  
• 11 years agoHelpfull: Yes(1) No(0)
• 125
  since f(2)=f(1)+f(1)+7*1*1+4=19
  f(3)=f(2)+f(1)+7*2*1+4=41
  f(5)=f(3)+f(2)+7*3*2+4=106
  so,f(5)+f(2)=106+19=125
• 11 years agoHelpfull: Yes(1) No(0)
• f(2)=f(1+1)=f(1)+f(1)+7*1*1+4=4+4+7+4=19
  f(3)=f(1)+f(2)+7*1*2+4=4+19+18=41
  f(5)=f(2)+f(3)+7*2*3+4=19+41+70+4=106
  so f(2)+f(5)=106+19=125
• 11 years agoHelpfull: Yes(1) No(0)
• f(2)=f(1)+f(1)+7*1*1+4
  f(2)=19
  
  f(3)=f(2)+f(1)+7*2*1+4
  f(3)=19+4+14+4
  f(3)=31
  
  f(2+3)=f(5)=f(2)+f(3)+7*2*3+4
  19+31+42+4
  f(5)=96
  
  f(2)+f(5)= 19+96
  
• 11 years agoHelpfull: Yes(0) No(0)
• f(1)=4(given)
  f(2)=f(1+1)=f(1)+f(1)+7*1*1+4=19
  f(3)=f(2+1)=41
  similarly,f(5)=106
  so,f(2)+f(5)=125
• 11 years agoHelpfull: Yes(0) No(1)
• If f(1)=4 and f(x+y)=f(x)+f(y)+7xy+4
  f(1+1)=f(1)+f(1)+7(1)(1)+4
  f(2)=4+4+7+4=19
  f(3)=19+4+14+4=51
  f(5)=f(3)+f(2)+7(3)(2)+4=51+19+42+4=116
  f(2)+f(5)=19+116=135
• 11 years agoHelpfull: Yes(0) No(1)