Question

Resposta da conta:

12/y-1= 3y/5

[ Método de multiplicar cruzado]

Answer 1

  12        3y
------- = ------
 y -1        5

3y.y +3y.-1 = 12.5
3y² -3y -60 = 0
3(y² -y -20) = 0

y² -y -20 = 0
Δ = b² - 4.a.c
Δ = -1² - 4.1.-20
Δ = 1 + 80
Δ = 81

y = -b +- √Δ / 2a
y = -(-1) +- √81 / 2.1
y = 1 +- 9/2

y' = 1 +9/2                           y'' = 1 -9/2
y' = 10/2                              y'' = -8/2
y' = 5                                   y'' = -4

S = {5, -4}

Answer 2

12/(y-1)= 3y/5
3y(y-1)=5.12
3y²-3y=60
3y²-3y-60=0 (dividindo por 3)
y²-y-20=0
a=1
b=-1
c=-20
Δ=b²-4ac
Δ=(-1)²-4.1.(-20)
Δ=1+80
Δ=81
y=-b±√Δ/2a
y=-(-1)±√81/(2.1)
y=(1±9)/2
y'=(1+9)/2
y'=10/2
y'=5

y"=(1-9)/2
y"=-8/2
y"=-4

S{-4 , 5}