X = Ancho
2X + 5 = Largo
Area = (2X + 5)X = 2X² + 5X
Area = 75 m²
2X² + 5X = 75
2X² + 5X - 75 = 0
Donde : a = 2 ; b = 5 ; c = - 75
<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-%285%29%5Cpm%20%5Csqrt%7B%285%29%5E2-4%282%29%28-75%29%7D%7D%7B2%282%29%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B-%285%29%5Cpm%20%5Csqrt%7B25%2B600%7D%7D%7B4%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B-5%5Cpm%20%5Csqrt%7B625%7D%7D%7B4%7D" />
<img src="https://tex.z-dn.net/?f=X%3D%5Cfrac%7B-5%5Cpm%20%5C%2025%7D%7B4%7D" />
X1 = [ - 5 + 25] / 4 = 20 / 4 = 5
X2 = [ - 5 - 25] / 4 = - 30 / 4 = - 15 / 2
Uso X1 = 5
X = 5 metros
Ancho = 5 metros
2X + 5 = Largo
2(5) + 5 = 15 m
Largo = 15 metros
Area = 5 x 15 = 75 m².