Question

Quais sao as raizes da equação.
A) 2x² - 10x = 0
B) X² - 4x + 3 = 0

Answer 1

a) $2x^2-10x=0$

$x(2x-10)=0$

$x=0$ ou $2x-10=0~~\Rightarrow~~x=5$

$S=\{0,5\}$

b) $x^2-4x+3=0$

$\Delta=(-4)^2-4\cdot1\cdot3=16-12=4$

$x=\dfrac{-(-4)\pm\sqrt{4}}{2}=\dfrac{4\pm2}{2}=2\pm1$

$x'=2+1=3$ e $x"=2-1=1$

$S=\{1,3\}$

Answer 2

A) 2x² - 10x = 0
    X(2X-10)=0
    X'=0 e 2X-10=0
             2X=10
             X=10/2
             X''=5
resp: X=0 e X=5

B) X² - 4x + 3 = 0
   a=1 b=-4 c=3
delta=b²-4ac
delta=(-4)²-4(1)(3)
delta=16-12
delta=4
raiz de delta= 2

X'=(-b+raiz de delta)/2a
X'= [-(-4)+2]/2(1)
X'= (4+2)/2
X'=6/2
X'=3

X''=(-b-raiz de delta)/2a
X''= [-(-4)-2]/2(1)
X''= (4-2)/2
X''=2/2
X''=1

resp: X=1 e X=3