A spring stretches in relation to the weight hanging from it according to the equation \(\text{y} = 0.75\text{x} + 0.25\) where x is the weight in pounds and y is the length of the spring in inches.
A music school charges a registration fee in addition to a fee per lesson. Music lessons last 0.5 hour. The equation \(\text{y} = 40\text{x} + 30\) represents the total cost y of x lessons. Find and interpret the slope and y-intercept of the line that represents this situation. Then find four points on the line.