Question

5.
If 7a - 5b = 6 and ab = 9. then find the value
of 343a3 – 125b3​

Answer 1

Answer:

Step-by-step explanation:

7a - 5b = 6

ab = 9

(7a - 5b)³ = (7a)³ - (5b)³ - 3 (7a)(5b)(7a - 5b)

    (7a)³ - (5b)³   = (7a - 5b)³ + 3 (7a)(5b)(7a - 5b)

   343a³ – 125b³   = 6³ + 3 x 35 x 9 x 6

                              = 216 + 5670

                              = 5886