Question

the length and breadth of a rectangle are (8y-21) and (12y+7) respectively. find it's perimeter​

Answer 1

Given ,

length = ( 8y - 21 )

breadth = ( 12y + 7 )

perimeter of a rectangle = 2( l + b )

$=2( (8y - 21) + (12y + 7) )\\ \\ = 2(8y - 21 + 12y + 7) \\ \\ = 2(20y - 14) \\ \\ = (40y - 28) \: \: \: unit .$