Question

dad a função real f(x)=x2-5x+4 os zeros são

2e5
5e4
1e4
2e2
1e2 ?

Answer 1

-b/c = 5/4 = 1+4/1•4 ==> x'=1 , x"=4

Answer 2

${x}^{2} - 5x + 4 = 0$

$a = 1 \: b = -5 \: c = 4$

$delt a= {b}^{2} - 4ac$

$= {-5}^{2} - 4 \times 1 \times 4$

$= 25 - 16$

$= 9$

$x12 = \frac{ - b + - \sqrt{delta} }{2a}$

$x12 = \frac{ 5 + - \sqrt{9} }{2 \times 1}$

$x12 = \frac{ 5 + - 9}{2}$

$x1 = \frac{ 5 + 9}{2}$

$x1 = \frac{14}{2} =7$

$x2 = \frac{ 5 - 9}{2}$

$x2 = \frac{ 14}{2} = 7$

solução :(2,-7)