Solve for x pls help

What is the solution to this system of equations? y= 2x - 3.5 x - 2y = -14

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.

Juanita wade's new car has an msrp of $28,902.11 including title and processing fees. the premier package which includes surround sound and dvd player costs three times the amount of the in-style package which includes leather seats and select wheels. the total cost of her new car was $34,290.08 which included the 6.5% sales tax. find the cost of the premier package to the nearest cent.