Question

(x-y) 3=x3-y3-3xy(x-y)
prove this​

Answer 1

L.H.S : ( x - y ) ³

={ ( x - y ) ( x - y ) ( x - y ) }

= {( x - y ) ² ( x - y ) }

= { x² + y² - 2xy ( x - y ) }

= { x - y ( x² + y² - 2xy ) }

= x³ + xy² - 2x²y - x²y - y³ + 2xy²

= x³ - y³ + xy² + 2xy² - 2x²y- x²y

= x³ - y³ + 3xy² - 3x²y

= x³ - y³ - 3xy ( x - y ) = R.H.S

Hence Proved