<span>the line through points (-1,-2) and (5,3)
slope=(3-(-2))/(5-(-1))=5/6
for a perpendicular line slope =-6/5=-1.2
y=(-6/5)x+b
7=(-6/5)*3+b
7=-18/5+b
7=-36/10+b
7=-3.6+b
b=10.6
y=-1.2x+10.6</span>
Repeating decimals are rational
Starting with a different number changes the diagram because if you started with any other number, you would get different results.
To do this problem, you need to find how many questions per minute she can do. You would need to do 21 divided by 14. Which equals 1.5 questions per minute. From there you would do 1.5 times 30 and get 45.
So she can get 45 questions in 30 minutes.
Hope that helps!!
