Question

8- Dando o sistema {5^x-y=1/125
{3^x+y=243

*Calcule o valor de (x.y)^3

Answer 1

5^x - y =1/125
5^x - y = 1/5³
5^x - y = 5^-3
x - y = - 3(I)

3 ^x + y = 243
3^x + y = 3^5

x + y = 5 (II)
X - Y = -3
--------------------
2 X = 2
X = 2/2
X = 1
SUBSTITUI X
X + Y =  5
1 + Y = 5
Y = 5 - 1
Y = 4

CALCULE 
(X.y)³ = (1.4)³  = 4³ = 4.4.4 = 64