Which equation represents the length of the completed tunnel based on the number of days since tbm was introduced?

during a tunnel construction project, engineers used explosives to excavate partway into a mountain. but due to constraints and environmental concerns, they later introduced a tunnel boring machine (tbm) to excavate the rest of the tunnel. the length and of the completed tunnel (in feet) is based on the number of days since the tbm started working. the length can be calculated using the equation y = 25x + 225. what does the y-intercept represent in this scenario?

during a construction project, engineers used explosives to excavate 140 feet of tunnel into a mountain. but because of time constraints and environmental concerns, they brought in a tunnel boring machine (tbm) to excavate the rest of the tunnel. the data table lists some observations an engineer made about the length of the tunnel after the tbm was introduced.

which equation represents the length of the completed tunnel based on the number of days since tbm was introduced?

the answer is y = 45x + 140

it would open into a square depending on the type of envelope i’m not sure about the second part