What is the value of c when the expression 21.2x + c is equivalent to 5.3(4x − 2.6)?

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

Complete the equation of the line through (−10,3) and (−8,−8). use exact numbers.

Need on this one asap im almost done with this subject