Respuesta :

To solve the exercirses which are shown in the figure attached, you must follow the proccedure below:

 7) (x)=x³-6x²+8x
 (x)=x(x³-6x²+8)
 (x)=(x-4)(x-2)x

 The lenght is: x
 The height is= (x-4)

 8) √(2x+8)-6=4

1. You need to clear the variable "x". Then:

 √(2x+8)=4+6
 √(2x+8)=10
 (√2x+8)²=10²
 2x+8=100
 2x=100-8
 x=92/2
 x=46

 9) l4x+3l=9+2x

 1. To solve the left member, you must evaluate two cases: it could be positive,or negative. Then:

 2. Negative:

 l4x+3l=9+2x
 -4x-3=9+2x
 -4x-2x=9+3
 -6x=12
 x=12/-6
 x=-2

 3. Positive:

 l4x+3l=9+2x
 4x+3=9+2x
 4x-2x=9-3
 2x=6
 x=6/2
 x=3