F.2 indics

1.5X + 5X+1 - 150=0
5X + (5)(5X) - 150=0
6(5X)=150
5X=25
5X=52
x=2
2. If xy=1, find the value of 2^(x+y)^2/2^(x-y)^2
2^(x+y)^2/2^(x-y)^2
=2^(x2+2xy+y2)/2^(x2-2xy+y2)
=2^[(x2+2xy+y2)-(x2-2xy+y2)]
=2^(x2+2xy+y2-x2+2xy-y2)
=2^(2xy+2xy)
=2^(4xy)
=2^4
=16






2013-09-22 12:35:49 補充：
寫靚d先...>.<

1. 5^X + 5^(X+1) - 150=0
5^X + (5)(5^X) - 150=0
6(5^X)=150
5^X=25
5^X=5^2
X=2