The matrix r= [ 12 4 ] represents the length of 12in. and the width of 4 in. of a rectangle. if matrix multiplication is used to double the length and width of the rectangle, which rectangle represents the result of the matrix multiplication?

Afarmer has a large field that is x feet in length. he wants to fence in a rectangular section in the middle of the field , leaving a length of 100 feet of open field behind each end of the fenced rectangle.he also wants the width of the fenced-in space to be 100 feet less than its length. find the expressions to represent the length and width of the fenced section of the field