Jika x=3-2√7 dan y=3+2√7 tentukan nilai C.x+y:x-y D.x⁴-y⁴

#F

Jika x=3-2√7 dan y = 3+2√7, maka :

x. y = (3 – 2√7)(3 + 2√7) = 9 – 28 = – 19

x + y = 3 – 2√7 + 3 + 2√7 = 6

x – y  = 3 – 2√7 – 3 –  2√7 = – 4√7

*

C) (x + y) ; (x -y) = 6/(- 4√7) = (6√7)/(-28) = – (3/14) √7

D). x⁴-y⁴ = (x² + y²)(x² – y²)

= ((x+y)² – 2(xy)} {(x+y)(x-y)}

= {6² – 2(-19)} {6)(-4√7)

= { 36+38}{-24√7}

= 74(-24√7)

= 1.776√7