Question

x^2 + 1/25x^2 = 43/5, find (a) 5x + 1/x, (b) 25x^2 - 1/x^2.​

Answer 1

Answer:

sorry I am weak in math

so I don't know

Answer 2

Answer:

Let : x² + ( 1/ 25x² ) = 43/5 ...... (1)

∴ x² + ( 1/ 25x² ) + (2/5) = (43/5) + (2/5)

∴ ( x + 1/ 5x )² = 9

∴ x + ( 1/ 5x ) = ± 3 ................. (2)

∴ from (1) and (2),

... x³ + ( 1/ 125x³)

= x³ + ( 1/ 5x )³

= ( x + 1/ 5x ) [ ( x² + 1/ 25x² ) - (x)(1/ 5x) ]

= ( ± 3 ) [ ( 43/5 ) - ( 1/5 ) ]

= ( ± 3 )( 42/5 )

= ± 126/5