Question

Si: x-y=3;xy=5 Hallar: E=x3+y3

Answer 1

Respuesta:

Explicación paso a paso:

a³ + b³ = (a+b)(a²-ab+b²)

(m+n)² = m²+ n² + 2mn

x³ + y³ = (x + y)(x²-xy+y²)

x³ + y³ =   (5)(x²+y²-3)  

`Para hallar x²+y²

(x+y)² = x² + y² + 2xy

 5² = x² + y² + 2(3)

 25 = x² + y² + 6

25-6 = x² + y²

  19 = x² + y²

x³ + y³ =   (5)(x²+y²-3)  

x³ + y³ = (5)(19-3)

x³ + y³ = 5(16)

x³ + y³ = 80