High amount of points! math question! if you don't know it, don't answer!

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Graph the line with the given slope m and y-intercept b. m=-3,b=1

20 points for the answer. this is for real , don't put random ! a rectangle has a length of 4 centimeters and a width of 7 centimeters. what is the effect on the perimeter when the dimensions are multiplied by 5? the perimeter is increased by a factor of 5. the perimeter is increased by a factor of 20. the perimeter is increased by a factor of 25. the perimeter is increased by a factor of 100.