Please solve question no. 7 with proper explanation 

Asked by adityaahuja099 | 11th Dec, 2017, 09:03: PM

Expert Answer:

begin mathsize 16px style straight x over straight y plus straight y over straight x equals negative 1
rightwards double arrow fraction numerator straight x squared plus straight y squared over denominator xy end fraction equals negative 1
rightwards double arrow straight x squared plus straight y squared equals negative xy space space space space space space space space.... left parenthesis straight i right parenthesis
Now comma space straight x cubed minus straight y cubed
equals left parenthesis straight x minus straight y right parenthesis left parenthesis straight x squared plus xy plus straight y squared
equals left parenthesis straight x minus straight y right parenthesis left square bracket xy plus left parenthesis straight x squared plus straight y squared right parenthesis right square bracket
equals left parenthesis straight x minus straight y right parenthesis left square bracket xy plus left parenthesis negative xy right parenthesis right square bracket space space space space space..... From space left parenthesis straight i right parenthesis
equals left parenthesis straight x minus straight y right parenthesis cross times 0
equals 0 end style

Answered by Rashmi Khot | 12th Dec, 2017, 10:02: AM