Question

3x(dois ao quadrado)-7x+2=0

Answer 1

Boa noite!

Δ = b² - 4ac 
Δ = (-7²) -4*3*2
Δ = 49-4*3*2
Δ = 49-(24) 
Δ = 25

X1 = -b + √ Δ/2*a
X1 = -(-7) + √25/2*3
X1 = (7) + 5/6
X1 = 12/6
X1 = 2

X2 = -b - √ Δ/2*a
X2 = -(-7) - √25/2*3
X2 = (7) - 5/6
X2 = 2/6
Simplificando:
X2= 1/3

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Answer 2

$3x^2-7x+2=0\\\\a=3\ \ \ b=-7\ \ \ \ c=2\\\\\triangle=b^2-4ac\\\triangle=(-7)^2-4\cdot(3)\cdot(2)\\\triangle=49-24\\\triangle=25\\\\\\x= \dfrac{-b \frac{+}{-} \sqrt{\triangle} }{2a}$

$x= \dfrac{-(-7) \frac{+}{-} \sqrt{25}}{2\cdot(3)}\\\\\\x= \dfrac{7 \frac{+}{-}5 }{6}\\\\\\x'= \dfrac{7+5}{6}\\\\\\x'= \dfrac{12}{6}\\\\\\x'=2\\\\\\x"= \dfrac{7-5}{6}\\\\\\x"= \dfrac{2}{6} \\\\\\Simplificando\\\\\\x"= \dfrac{2}{6}: \dfrac{2}{2}\\\\\\x"= \dfrac{1}{3}$

$\boxed{S=\bigg\{\bigg( \dfrac{1}{3},2 \bigg)\bigg\}}$