Răspuns:
Explicație pas cu pas:
1)
2/21*21/4-3*12/6
= se simplifica 21 cu 21 ...4 cu 2 ........3 cu 6
= 1/2-11/2
= -10/2
= -5 ( B)
-
2)
a= 4√3=√48
b= 5√2=√50
√48<√50
a<b ( C)
3)
√6=2,44 (D)
4)
x+y=5
x-y=3
2x= 5+3
2x=8
x=8:2
x=4 ( A)
5)
a+b=25
a-b=13
a= 13+b
13+b+b=25
2b= 25-13
2b=12
b=12:2
b= 6
a=25-6
a= 19 ( B)
6)
Lc= 2πR
Ad= πR²
8π=2πR
R=8π/2π
R=4 cm
A= π*4²
A=16π cm² (C)
