Question

VALENDO 54 PONTOS COLOQUE NA FORMA GERAL E RESOLVA

Answer 1

a) x² - 7x +10= 0               a=1,     b=-7    , c=10

x= -b +ou -√b² - 4.a.c / 2a
x= - (-7) +ou - √ (-7)² -4(1)(10) / 2(1)
x= +7 +ou - √49 -40 / 2
x= +7 +ou- √9   / 2
x=+7 +ou- 3/ 2               x'=7 +3 /2 = 10/2 =5
                                      x''= 7-3/2= 4/2 = 2

b) 2x² -10x -12=0      a=2,      b=-10,      c=-12

x= -(-10)+ou-√(-10)² - 4(2)(-12) / 2.2
x= +10 +ou- √ 100 + 96 / 4
x = +10 +ou- √196 /4
x= +10 +ou- 14 / 4          x'=10+14/4=24/4= 6
                                       x''= 10-14/4=-4/4= -1
c) 8x² -7=0
     8x²= 7
       x² =7/8
       x = +ou- √7/8           x'= +√14/4,     x''=-√14 /4

d) 9x² -12x -1=0     a=9,    b=-12,     c=-1

x=-(-12)+ou-√(-12)² - 4(9)(-1) / 2.9
x=12 +ou- √144+36 /18
x= 12+ou- √180 / 18
x= 12+ou- 6√5 / 18               x'= 12+6√5 / 18= 2+√5 /3
                                             x''= 12-6√5 /18= 2-√5 / 3 

Answer 2

a) x² - 7x + 10 = 0        a = 1 b = -7 c = 10
 Δ = 49 - 40
 Δ = 9
x = 7 +-√9/2
x = 7 +-3/2
x' = 10/2 = 5
x'' = 4/2 = 2

b) 2x² - 10x -12 = 0       a = 2 b = -10 c = -12
Δ = 100 + 96
Δ = 196
x = 10 +-√196/4
x = 10 +-14/4
x' = 24/4 = 6
x''= -4/4 = -1

c) 8x² - 7 = 0          a = 8 b = 0 c = -7
Δ = 0 + 224
Δ = 224
x = 0 +-√224/16
x = +-√224/16
x' = √224/16
x'' = -√224/16

d) - 9x² + 12x + 1 = 0         a = -9  b = 12 c = 1
Δ = 144 + 36
Δ = 180
x = -12 +-√180/-18
x = -12 +-13,4/-18
x' = -12 +13,4/-18
x' = 1,4/-18 ≈ - 0,077
x'' = -12 - 13,4/-18
x'' = -25,4/-18 ≈ 1,41     ok