Answer
Slope: if the fat content increases $1~g$, it is expect that calories will increase by $13.738$
y-intercept: if a cheeseburger has no fat (fat content equal to 0), then it is expected that there will be 150.798 calories in this cheeseburger.
Work Step by Step
We could also have said that when the fat content increases by $1~g$, the calories increase by $13.738$, on average.
For the y-intercept, just make $x=0$ in the least-squares regression line.
