Question

De la 1 pana la 4 va rog frumos ​

Answer 1

Răspuns:

1.r= a3-a2= 5-3= 2

a1= a2-r= 3-2=1

2. f(n)=3

n^2-1=3

n^2= 4-----> n=+/- 2

f(2)=2^2-1= 4-1= 3 (A)

3.x^2-9= (x+3)^2

Dacă ridicăm tot la pătrat se obține: x^2-9= x^2-2x+1

-2x= -10------> x= 5

Verificare: 5^2-9= 5^2-2×5+1---->

---->16= 16

4. {1,2,3,4}

( 1,2,3), (2,3,4), (1,2,4), (1,3,4) -deci 4.

Succes!