4 - (x + 6)
or -x -2
.......
The whole wall area including the window is 150 ft squared (15 ft x 10 ft). The window is 50 square feet (5 x 10). Take the whole area and subtract the window area and you have 100 sq ft thats paintable. One can is 50 sq ft so 100/50 is 2 cans of paint needed. Your answer is H.
(1) The train travels 4 miles per gallon.
(2) The slope of the graph is 
Explanation:
(1) The miles that train travels per gallon is given by

Dividing, we have,

Thus, the train travels 4 miles per gallon.
(2) To determine the slope, let us consider two points from the graph.
The coordinates are
and 
Thus, substituting the coordinates in the slope formula, we get,

Simplifying, we have,

Thus, the slope of the graph is 
You multiply the new answer with the number before