contestada

The diagram shows two joined rectangles. The total area of the compound shape ABCDEF is 36 cm^2. By considering the areas of the two rectangles, show that
2x^2 - 5x - 18 = 0 and hence find the value of length AB.

The diagram shows two joined rectangles The total area of the compound shape ABCDEF is 36 cm2 By considering the areas of the two rectangles show that 2x2 5x 18 class=

Respuesta :

Answer:

The value of AB is 9/2 or 4.5

mhanifa

Answer:

4.5 cm

Step-by-step explanation:

The total area is the sum of areas of two rectangles:

  • x(x-4)+3x(x-2)=36
  • x²-4x+3x²-6x-36=0
  • 4x²-10x-36=0
  • 2x²-5x-18=0
  • 2x²-9x+4x-18=0
  • x(2x-9)+2(2x-9)=0
  • (x+2)(2x-9)=0
  • x+2=0 ⇒ x= -2  discarded as negative
  • 2x-9=0
  • 2x=9
  • x=4.5
  • AB=4.5 cm

Otras preguntas