Question

( 1 ) Resolva as Equações do 2° grau.




( A ) 3x² - 5 x + 2 = 0 ( B ) - x² + 2x + 1 = 0




( C ) x² + 14x + 49 = 0







( D ) 2x² - 4x + 1 = 0 ( E ) y² + 2y + 2 = 0 ( F ) x² - 2x - 3 = 0








( G ) - 2x² + 7x - 2 = 0 ( H ) x² + 10x + 25 = 0 ( I ) 3y² + 6y - 24 = 0

Answer 1

a) 3x²-5x+2=0
Δ= (-5)² - 4.3.2
Δ= 25-24=1

x'=-(-5)+√1/2.3
x'= 5+1/6
x'=1

x"=-(-5)-1/2.3
x"=5-1/6
x"=2/3

b) -x²+2x+1=0
Δ=2²-4.(-1).1
Δ=4+4=8

x'=-2+√8/-2
x"=-2-√8/2

Answer 2

Olá Wagner 

( A ) 3x² - 5x + 2 = 0    ⇒ x1 = 1, x2 = 2/3
( B ) -x² + 2x + 1 = 0    ⇒ x1 = 1 + √2 , x2 = 1 - √2
( C ) x² + 14x + 49 = 0 ⇒ x1 = x2 = -7
( D ) 2x² - 4x + 1 = 0    ⇒ x1 = (2 + √2)/2 , x2 = (2 - √2)/2
( E ) y² + 2y + 2 = 0     ⇒  não existe raiz real
( F ) x² - 2x - 3 = 0       ⇒ x1 = 3, x2 = -1
( G ) -2x² + 7x - 2 = 0 ⇒ x1 = (7 + √33)/4 , x2 = (7 - √33)/4
( H ) x² + 10x + 25 = 0 ⇒ x1 = x2 = -5 
( I ) 3y² + 6y - 24 = 0   ⇒ y1 = 2, y2 = -4 

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