With the given order of integration, the interval over D is

Ok the numbers r
16/3 x+ 29/3
No they would be intersecting. x=-1 is a vertical line down the x axis on -1. y=2 is a horizontal line at 2 on the y axis.
A*5+b*2=145
a +b =50 | * -2
5a +2b=145
-2a -2b = -100
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5a-2a = 145-100
3a= 45
a=45:3
a=15 questions are worth 5 p
b=50-15=35 questions worth 2 p