Respostas

2014-09-01T19:04:24-03:00
Semelhança
 \frac{12}{x} = \frac{x-5}{x+7}
12x+84 = x² - 5x
x²-5x = 12x + 84
x² - 17x - 84 = o
Δ = 289 +336
Δ = 625

x = 42/2
x = 21

valor de y,

 \frac{20}{y}  \frac{16}{14}
16y = 280
y = 280/16
y = 17,5

26 4 26