Remember you can add like terms exg, 3y+4y=7y 3y^2+4y^2=7y^2, but cannot add 3y^2 and 4y, or 3 and 4y so
3a+2w-5a-9w
group like trems
3a-5a+2w-9w
subtract
-2a-7w
3y^2+2w^2-y^2-w^2
group like terms (think of w^2 and y^2 as 1w^2 and 1y^2)
3y^2-y^2+2w^2-w^2
subtract
2y^2+w^2
2x+2x=4x
The average speed would be 53 miles per hour, hope this helped, if you need me to explain then here is the way, so all you do is divide 265 by 5 and what I did to help make it faster was split 265 into 250 and 15 so 250 divided by 5 is 50 and 15 divided by 5 is 3 so 50 + 3 = 53!