Question

2的x次方等于4的(y-1)的次方,27的y次方=3的(x十1),则(x -1)=?

Answer 1

2^x=4^(y-1)
2^x=(2^2)^(y-1)
2^x=2^(2y-2)
x=2y-2
27^y=3^(x+1)
(3^3)^y=3^(x+1)
3^3y=3^(x+1)
3y=x+1
3y=2y-2+1
3y=2y-1
3y-2y=-1
y=-1
x=2y-2
=2*(-1)-2
=-4
x-1
=-4-1
=-5