Respuesta :
Answer:
105 = (w+8) *w
w = 7 cm
l = 15 cm
Step-by-step explanation:
Area of a rectangle is
A = l*w
l = w+8
105 = (w+8) *w
Distribute
105 = w^2 +8w
Subtract 105 from each side
105-105 = w^2 +8w -105
0 =w^2 +8w -105
Factor
What 2 number multiply to 105 and add to 8
15*-7 = -105
15-7 = 8
(w+15) (w-7) =0
Using the zero product property
w+15 =0 w-7 =0
w=-15 w=7
impossible
not negative
w =7
l = 15
Answer:
Width: w
Length: w + 8
w(w + 8) = 105
w² + 8w - 105 = 0
w² + 15w - 7w - 105 = 0
w(w + 15) - 7(w + 15) = 0
(w + 15)(w - 7) = 0
w = -15, 7
width = 7cm
length = 7+8 = 15cm