Question

sendo f(×) = 2x^2 - 3x + 1, calcule:

a) f(-1/2)
b) x, sabendo que f(x)= 0

Answer 1

f(-1/2) = 2(-1/2)² - 3(-1/2) + 1

2(1/4) - 3(-1/2) + 1

(2/4) - (-3/2) + 1

2/4 + 3/2 + 1

1/2 + 3/2 + 1

4/2 + 1

2 + 1

3

Então f(-1/2) = 3

b)

f(x) = 2x² - 3x + 1 = 0

2x² - 3x + 1 = 0

a = 2

b = -3

c = 1

aplicando bhaskara

delta = b² - 4ac

delta = 9 - 8

delta = 1

x = (-b +- $\sqrt{delta}$) / 2a

x = (3 +- 1) / 4

Daqui tiramos que

x1 = (3 + 1) /4

x1 = 4/4 = 1

x2 = (3 - 1) /4

x2 = 2/4 = 1/2