Find $[(4/7) ^3-(3/7) ^3]/ [(4/7) ^2-(3/7) ^2]$ =?
31/49
39/49
37/49
34/49
Explanation:
From the question,
$(4/7) ^3-(3/7) ^3$= $[(4^3) -(3^3)]/ (7^3)$
= $(64-27)/ (7^3)$
=37/343.
And,
$(4/7) ^2-(3/7) ^2$=$ [(4^2) -(3^2)]/ (7^2) $
= $[16-9]/ (7^2)$ =7/49.
Therefore, the required answer:
=> (37/343)/ (7/49) = (37 $\times$ 49/343)/7
=> (37/7)/7 = 37/49.