Question

Dada a equação 2x²-5x+3=0 e sabendo que suas raízes são x' e x", calcule x'+x".
a)1/2
b)3/2
c)5/2
d)12/5
e)16/25

Answer 1

2x² - 5x + 3 = 0

Soma das raízes (S) = $\frac{-b}{a}$
c = -5
a = 2

S = $\frac{-(-5)}{2}$
S = $\frac{5}{2}$

Answer 2

2x^2 - 5x + 3 = 0

a = 2
b = - 5
c = 3

Delta = b^2 - 4.a.c
Delta = (- 5)^2 - 4.2.3
Delta = 25 - 24
Delta = 1

x = - b +- VDelta / 2.a
x = - (- 5) +- V1 / 2.2
x = 5 +- 1 / 4

x' = 5 - 1 / 4
x' = 4/4
x' = 1

x" = 5 + 1 / 4
x" = 6/4 (÷ 2)
x" = 3/2

-------------------

x' + x"
1 + 3/2
2/2 + 3/2
=> 5/2

R: Alternativa c.