Question

Помогите пожалуйста!!!!!!

Answer 1

1.

$(x+1)^{2}=x^2+2x+1>x^2+2x=x(x+1)$

$a^2+1-6a+8=(a+3)^2\geq 0$

2.

$13x>13y$

$-5.1x<-5.1y$

$2.6y<2.6x$

3.

$16.5<5\sqrt{11} <17\\-6.6>-2\sqrt{11}>-6.8$

4.

$21.4<P<21.8\\28.06<S<29.14$