Question

preciso urgente pfvor me ajudeem!

Answer 1

   |a|   |b|    |c|
a) x² - 7x + 10 = 0

Δ = b² -4.a.c
Δ =(-7)²-4.1.10
Δ =(-7)² - 40
Δ = 49 - 40
Δ = 9
 
-b +/- √Δ ÷ 2.a
-(-7)+/- √9 ÷ 2
  7 +/- 3 ÷ 2
  x' = 7+ 3 ÷ 2 ------> x' = 10 ÷ 2 = [ 5 ]
  x"= 7 - 3 ÷ 2 ------> x" = 4 ÷ 2 = [ 2 ]
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b) 6x² +5x + 1 = 0
  
  Δ = 5² -4.6.1
  Δ = 5² - 24
  Δ = 25 - 24
  Δ = 1

 -5 +/- 1 ÷ 2
x' = -5 + 1 ÷ 2 ------> -4 ÷ 2 = [ -2 ]
x" = -5 -1 ÷ 2 -------> -6 ÷ 2 = [ -3 ]
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c) 25x² -20x + 4 = 0
  
Δ = 20² -4.25.4
Δ = 20² - 400
Δ = 400 - 400
Δ = 0

-(-20) +/- 0 ÷ 2.25
 x' = 20+0 ÷ 50  ---> x' = 0,4
 x" = 20-0 ÷ 50  ---> x" = 0,4
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-9x² = 5 -6x
-9x² + 6x - 5 = 0

Δ = 6² -4.(-9).(-5)
Δ = 6² -4.45
Δ = 6² - 180
Δ = 36 - 180
Δ = -144

-6 +/- √-144 ÷ 2.(-9)
-6 +/- 12i ÷ -18
x' = -6 + 12i ÷ -18 ------> x' = 6i ÷ -18 ------> x' = 0,333...i
x"= -6 - 12i ÷ -18 -------> x" = 18i / 18 ------> x" = -i