Question 116518
a. Sometimes. y=5 has no x intercept. y=x+1 has an x intercept of x=-1.
b. Sometimes. y=5x has a positive constant. y=-5x has a negative constant. 
c. A zero slope has no rise and is a horizontal line while an undefined slope has no run and is a vertical line.
d. the rise over the run or what angle it makes with the y axis. Small slope values are shallow and have small angles with the y axis while large slope values are steep and make large angles with the y axis.