Simplify 2a + 4 - 7a + a.
-a
0
-4a + 4
10a + 4

Aplane flies around trip to philadelphia it flies to philadelphia at 220 miles per hour and back home with a tailwind at 280 miles per hour if the total trip takes 6.5 hours how many miles does the plane fly round trip

Can anyone me with 32,33,36,37,and 40.

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?