[(4/7)^3-(3/7)^3]/[(4/7)^2-(3/7)^2]
a) 31/49
b) 39/49
c) 37/49
d) 34/49

• whole can be simplified as =(1/7)*(64-27)/(16-9)
  =37/49
• 11 years agoHelpfull: Yes(7) No(0)
• use formula: a^3-b^3=(a-b)(a^2+ab+b^2).
  and a^2-b^2=(a+b)(a-b).....expand the question in this form u will get answer easily.
  
• 11 years agoHelpfull: Yes(7) No(1)
• (4/7)^3-(3/7)^3=((4^3)-(3^3))/(7^3)
  =(64-27)/(7^3)
  =37/343
  (4/7)^2-(3/7)^2=((4^2)-(3^2))/(7^2)
  =(16-9)/(7^2)
  =7/49
  
  ans=(37/343)/(7/49)
  =(37*49/343)/7
  =(37/7)/7
  =37/49
• 11 years agoHelpfull: Yes(5) No(0)
• a^3-b^3=(a-b)(a^2+ab+b^2)&a^2-b^2=(a+b)(a-b)
  (4/7-3/7)((4/7)^2+4/7*3/7+(3/7)^2)/((4/7+3/7)(4/7-3/7))=37/49
• 11 years agoHelpfull: Yes(1) No(0)
• [(4^3/7^3)-(3^3/7^3)]/[(4^2/7^2)-(3^2/7^2)];37/343*49/7=37/49..... the answer is c
• 11 years agoHelpfull: Yes(0) No(0)
• [(4/7)^3-(3/7)^3]/[(4/7)^2-(3/7)^2]=>((1/7)^3[4^3-3^3])/((1/7)^2[4^2-3^2])
  =>(64-27)/(7*7)=37/49
• 11 years agoHelpfull: Yes(0) No(0)
• by using formula (a^3 - b^3)/a^2 - b^2)..get the answer 31/49..
  
• 11 years agoHelpfull: Yes(0) No(2)