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

• f(2)=f(1+1)=f(1)+f(1)+7.1.1+4= 4+4+7+4 = 19
  f(3)=f(2+1)=f(2)+f(1)+7.2.1+4 = 19+4+14+4 = 41
  f(5)=f(2+3)=f(2)+f(3)+7.2.3+4= 19+41+42+4 = 106
  so, f(2)+f(5) = 19+106 = 125
• 9 years agoHelpfull: Yes(29) No(0)
• Ri8 answer is 125 okay
• 9 years agoHelpfull: Yes(2) No(2)
• f(2)= f(1+1)= f(1)+f(1)+7*1*1+4 = 4+4+11 = 19
  f(3)= f(2)+f(1)= 19+4 = 23
  f(5)= f(2)+f(3)= 19+23 = 42
  f(2)+f(5)= 19+42 = 61
  
  
• 9 years agoHelpfull: Yes(0) No(5)
• why x=1,2,2 and y=1,1,3????
  can anyone xplain me plzzzz????
• 9 years agoHelpfull: Yes(0) No(0)
• 19+106=125
• 9 years agoHelpfull: Yes(0) No(0)
• Ans is 125
• 9 years agoHelpfull: Yes(0) No(0)