since the graph has direct variation as data in x axis increases y also increases.
so we need to find how many miles travelled per galloon .
we distance travelled per gallon =total distance travelled/galoons of fuel used.

for part b) slope=rise/run



slope of the graph is 2
X = 4, -2 that should be the roots(zeros) of the function.
2. (D)
3. (B) Hope it helps