Question

sabendo que x² + y² =30 e xy= 5, determine o valor de:

a) (x + y)² =

b) (x - y)² =

Answer 1

Temos x^2+y^2=30 e xy=5

a) (x + y)^2= x^2+2xy+y^2
x^2+y^2+2xy
30+2×5
40
b) (x - y)^2= x^2-2xy+y^2
x^2+y^2-2xy
30-2×5
20