find the value of x and y

Students buying lunch at rockwell elementary school yesterday chose either burritos or pizza. 185 students chose burritos and 252 chose pizza. 1. estimate the number of students who brought lunch by rounding each number to the nearest hundred. 2. estimate how many students bought lunch by rounding each number to the nearest ten. 3. find the total number of students who brought lunch. which of your estimates is closer to the actual total? explain. 4. draw a figure on a sheet of paper. estimate how many pennies will fit inside the figure. check your prediction using pennies.

The floor plan of a room has a scale of 2.5 in.: 35 ft. in the drawing, the length of the room is 8 in. and the width of the room is 6 in. what is the perimeter of the actual room?

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?