A rectangular piece of glass, 5 decimeters long, 3 decimeters wide, the remaining part is a square. Known cut area is 71 square decimeters, then the remaining square area is______ Square decimeter

A rectangular piece of glass, 5 decimeters long, 3 decimeters wide, the remaining part is a square. Known cut area is 71 square decimeters, then the remaining square area is______ Square decimeter

Let the side length of the remaining square be a decimeter, from the meaning of the title: 3A + 5 · (3 + a) = 71, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 8A = 71-15, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp