Respuesta :

Answer:

Step-by-step explanation:

(a) Perimeter = 2[3x + 5 + 4x - 5] = 14x m

(b) Given perimeter = 42m

            14 x = 42

           x = 3m

      Length = 3x + 5 = 14m

      Width = 4x - 5 = 7m

(c) Area = (3x+5)(4x-5) = 12[tex]x^{2}[/tex] + 5x - 25

  when x = 4;    area = 12*16 + 20*4 - 25

  Area = 192 - 80 -25 = 159[tex]m^{2}[/tex]