Verified answer

1) sqrt(16x^2-25)не=0, 16x^2-25>=0,

16x^2-25>0, (4x-5)(4x+5)>0, (4x-5)(4x+5)=0,

4x-5=0, x=5/4,

4x+5=0, x=-5/4,

x<-5/4, x>5/4,

(-oo;-5/4)U(5/4;+oo)

2) D=(a+1)^2-4a^2=a^2+2a+1-4a^2=-3a^2+2a+1>0,

-3a^2+2a+1=0,

3a^2-2a-1=0,

D=16,

a1=-2/3, a2=1,

-(a+2/3)(a-1)>0,

(a+2/3)(a-1)<0,

-2/3<a<1,

(-2/3;1)