Write All Linear Equations in Slope-Intercept Form $y = \frac { 1 } { 2 } x + 129$

Multiple Choice

Write all linear equations in slope-intercept form.
-A driver wants to gauge the fuel efficiency of her vehicle at speeds of 30 mph and above. She notices that traveling at an average speed of 45 mph results in a rating of 39 mpg, whereas at an average speed of 50 mph,
Her car rates 29 mpg. Find a linear equation to model the gas mileage y for an average speed of x mph. Find the
Slope-intercept form of the equation of the line.

A) $y = \frac { 1 } { 2 } x + 129$
B) $y = - 2 x + 129$
C) $y = \frac { 1 } { 2 } x + 51$
D) $y = - 2 x + 51$