Răspuns:
13.
a. 5 rationale: [tex]\sqrt{1}[/tex]=1; [tex]\sqrt{4}[/tex]=2; [tex]\sqrt{9}[/tex]=3; [tex]\sqrt{16}[/tex]=4; [tex]\sqrt{25}[/tex]=5
25 irationale
b. 1+2+3+4+5=15
c. [tex]\sqrt{8}[/tex]
Explicație pas cu pas:
14.
A={-1 ; 1}
B= {[tex]\sqrt{9}[/tex]=3} x∈N
C={-4; 2}
-x-1= 3
-x=3+1
x=-4
x+1 = 3
x=3-1
x= 2
D ={ -[tex]\sqrt2}[/tex] - 1; [tex]\sqrt{2}[/tex] - 1 }
-x-1= [tex]\sqrt{2}[/tex]
-x = [tex]\sqrt{2}[/tex] + 1
x =- [tex]\sqrt{2}[/tex] -1
x+1 = [tex]\sqrt{2}[/tex]
x = [tex]\sqrt{2}[/tex] - 1
