a.
x = ancho
y = largo
2x + 2y = 2600
x + 300 = y
b.
2x + 2(x + 300) = 2600
2x + 2x + 600 = 2600
4x = 2600 - 600
4x = 2000
x = 500
500 + 300 = y
800 = y
