The perimeter of a rectangle is 48 cm. the length is 6 cm less than twice the width. which system would model this situation, and what are the length and the width?

Long division setup showing an incomplete calculation. 12 is in the divisor, 6839 is in the dividend, and 5 hundreds and 6 tens is written in the quotient. 6000 is subtracted from 6839 to give 839. an unknown value represented by a box is being subtracted from 839. what number should be placed in the box to complete the division calculation?