Question

sejam r¹ e r² as raizes da equação de 2 grau 2x²-6x+3=0 .Determine o valor de. A) r¹ +r² B)r¹•r² C)(r¹+3)•(r²+3)

Answer 1

a)r¹+r²
-b/a
r¹+r
-(-6)2
6/2=
3

b)r¹.r²
c/a
r¹.r²
3/2

c) (r¹ + 3)(r² + 3)
r¹r²+3r¹+3r²+9
r¹r²+3(r¹ + r²)+9
3/2+3.3+9
3/2+18=
39/2

Answer 2

r¹ + r² sendo as raízes temos:
a) r¹ + r² = -b/a => r¹ + r² = -(-6)2 = 6/2 = 3

b) r¹ .r² = c/a => r¹ . r² = 3/2

c) (r¹ + 3)(r² + 3) = r¹r² + 3r¹ + 3r² + 9 = r¹r² + 3(r¹ + r²) + 9 = 3/2 + 3.3 + 9 =

= 3/2 + 18 = (3 + 36)/2 = 39/2