Real answer
48
*26
------
1,248
Estimate
50
*25
------
1,250
So the answer is..
Estimating is helpful because it makes sure you answered correctly. No, this answer is incorrect and if he had done the estimate he could have seen how he was wrong.
To be able to determine the graph of this inequality, we'll start rearranging the inequality putting the "y" variable at the left side of the equation.

Since the inequality here is greater than or equal to, this means that the shade is above the solid line.
This equation also has a slope of -5 and y-intercept of 0.
Therefore, the graph of this equation looks like this: