1.5-x>=0,x-5>=0
x=5,y=2
x^y=5^2=25
2.a-1+a+3=2a+2=0,a=-1
x=(a-1)^2=(-2)^2=4
3.=√9=3
4.(x-1)^2=49
x-1=7或x-1=-7
x=8或x=-6