La plaza de un pueblo es de forma rectangular de 3500 metros cuadrados de área ?

Respuesta : <img src="https://tex.z-dn.net/?f=%5Cfbox%7BP%3D240%5C%2Cu%7D" />Explicación paso a paso : <img src="https://tex.z-dn.net/?f=%5Ctextbf%7BPara%20encontrar%20el%20per%5C%27imetro%2C%20encontremos%20el%20valor%7D%5C%5C%5Ctextbf%7Bde%20x%2C%20dicho%20valor%20se%20relaciona%7D%5C%5C%5Ctextbf%7Bcon%20su%20%5C%27area%2C%20entonces%20el%20%5C%27area%20se%20expresa%20como%3A%7D%5C%5C%5C%5CA%3Dbh%5C%5C%5Ctexbf%7Bdonde%3A%7D%5C%5Ca%3Dx%2B20%5C%5Cb%3Dx%2B40%5C%5C%5Ctextbf%7BDesarrollando%20nos%20queda%3A%7D%5C%5C3500%5C%2Cm%5E%7B2%7D%3D%28x%2B20%29%28x%2B40%29%5C%5C3500%3Dx%5E%7B2%7D%2B60x%2B800%5C%5C%5Ctextbf%7BSimplificando%3A%7D%20%5C%5Cx%5E%7B2%7D%2B60x%2B800-3500%3D0%5C%5Cx%5E%7B2%7D%2B60x-2700%3D0%5C%5C%5Ctextbf%7BResolviendo%3A%7D%5C%5Ca%3D1%5C%2C%5C%2C%2Cb%3D60%5C%2C%5C%2C%2Cc%3D-2700%5C%5Cx%3D%5Cfrac%7B-60%5Cpm%5Csqrt%7B%2860%29%5E%7B2%7D-4%281%29%28-2700%29%7D%7D%7B2%281%29%7D%5C%5Cx%3D%5Cfrac%7B-60%5Cpm%5Csqrt%7B3600%2B10800%7D%7D%7B2%7D%5C%5Cx%3D%5Cfrac%7B-60%5Cpm%5Csqrt%7B14400%7D%7D%7B2%7D%5C%5Cx%3D%5Cfrac%7B-60%5Cpm%20120%7D%7B2%7D%5C%5Cx_%7B1%7D%3D%5Cfrac%7B-60%2B120%7D%7B2%7D%3D%5Cfrac%7B60%7D%7B2%7D%3D30%5C%5Cx_%7B2%7D%3D%5Cfrac%7B-60-120%7D%7B2%7D%3D-%5Cfrac%7B180%7D%7B2%7D%3D-90%5C%5C%5Ctextbf%7BTomando%20la%20ra%5C%27iz%20positiva%2C%20nos%20queda%3A%7D%5C%5CP%3D2a%2B2b%5C%5CP%3D2%2830%2B20%29%2B2%2830%2B40%29%5C%5CP%3D2%2850%29%2B2%2870%29%5C%5CP%3D100%2B140%5C%5CP%3D240%5C%2Cu" />.