Respostas

2014-06-04T20:12:21-03:00
x+x²=90   arrumar a casa

x² + x - 90 = 0
a = 1
b = 1
c = -90
Δ = b² - 4ac
Δ = (1)² - 4(1)(-90)
Δ= 1 + 360
Δ= 361  ---------------------------√361 = 19

se 
Δ > 0 
então
x = -b - + 
√Δ/2a

x' =  - 1 - √361/2(1) 
x' = - 1 - 19/2
x' = - 20/2
x' = - 10

x" = - 1 + √361/2(1)
x" = - 1 + 19/2
x" = 18 /2
x" = 9

V = { -10, 9}
2014-06-04T21:16:19-03:00
×+×2=90
×3=90
×= 90/3
×=30

=D