Tarima Original
X = Ancho
X + 3 = Largo
Area = X(X + 3) = X² + 3X
Tarima modificada
X + 5 = Nuevo ancho
X + 3 + 4 = X + 7 = Nuevo largo
Area : = (X + 7)(X + 5) = X² + 5X + 7X + 35 = X² + 12X + 35 :
X² + 12X + 35 = 3(X² + 3X)
X² + 12X + 35 = 3X² + 9X
3X² - X² + 9X - 12X - 35 = 0
2X² - 3X - 35 = 0 : (Ecuacion del Sistema)
Donde : a = 2 ; b = - 3 ; c = - 35
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B-b%5Cpm%20%5Csqrt%7Bb%5E2-4ac%7D%7D%7B2a%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B-%28-3%29%5Cpm%20%5Csqrt%7B%28-3%29%5E2-4%282%29%28-35%29%7D%7D%7B2%282%29%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B3%5Cpm%20%5Csqrt%7B9%2B280%7D%7D%7B4%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B3%5Cpm%20%5Csqrt%7B289%7D%7D%7B4%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B3%5Cpm%20%5C%2017%7D%7B4%7D" />
X1 = [3 + 17] / 4 = 20 / 4 = 5
X2 = [3 - 17] / 4 = - 14 / 5 = - 2.
8
Tomo el valor positivo X = 5.
Probemos
Tarima original
Ancho = 5 m
Largo = 5 + 3 = 8 m
Area = 5 x 8 = 40 m²
Tarima modificada
Ancho = 5 + 5 = 10 m
Largo = 5 + 7 = 12 m
Area = 10 x 12 = 120 m²
Area original = 40 m²
Area modificada = 120 m²
Area modificada = (40 m²)x3 = 120 m²
Rta : Las dimensiones originales de la tarima son :
Ancho 5 metros, Largo 8 metros.