Question

1.解下列方程(5)(√2+1)^x+(√2-1)^x=6 (6){2^(x+3)+9^(y+1)=35,8^(x/3)

Answer 1

5.设(跟号2+1)^x=A,则(跟号2-1)^x=1/A

A+1/A=6

解得A=3+2跟号2 或3-2跟号2(舍)

所以x=2

6.{8*2^x+9*3^2y=35}

{2^x+3*3^2y=5}

解得2^x=4,3^2y=1/3

所以x=2,y=-1/2