Question

quais sao as dimensões de um retângulo cujo a medida da area e de 32 cm2 e a medida do perimetro e 24 cm

Answer 1

2x + 2y =24  : 2          x+y = 12      ---> x = 12 - y          (não é o x² nem x . 2)

x . y = 32                                               x= 12 - 4          x2= 12 -8

(12 - y)y = 32                                         x1= 8              x2=4

12y -y² =32                                            y1=4                y2=8

 -y² +12y -32 = 0

a = -1              Δ = b² -4.a.c                     y= -b +- √Δ          y= -12+-4    

b = 12            Δ =12² -4 . -1 . -32                    2.a                       -2

c = -32           Δ = 144 -128                       y= -12 +-√16         y1= -12 +4     =     -8 = 4

                      Δ= 16                                         2.-1                            -2               -2

y2= -12-4 =  -16 = 8

        -2           -2