Need help asap please show work

m<5= 75° Alternate angles are equal

m<6 = 180°-75°= 105 ° Angles on a straight line adds up to 180°

In a rectangle opposite sides are equal so AB= CD

2x+8= 3x+4

3x-2x=8-4 ( combine like terms, the signs will change since they are going over opposite sides)

x= 4

To solve for BC

AD= BC

x+17 ( we know that x=4)

4+17=21

Therefore BC= 21

what is all that apply?