Round 34 to 30 and round 89 to 90. Multiply 30 and 90 which equals to 2700.
Since density is the ratio of mass to (in this case) area, we can find the mass of the triangular region 
by computing the double integral of the density function over :
The boundary of is determined by a set of lines in the 
plane. One way to describe the region is by the set of points,
So the mass is
Distribute the -1 to (x+1)
Yes, I think I’m not sure correct me if I’m wrong .
Answers:
The second term is 2
The fifth term is 23
The ninth term is 51
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Explanation:
To find the second term, replace every n with 2 and use PEMDAS to simplify
a(n) = -5+(n-1)(7)
a(2) = -5+(2-1)(7)
a(2) = -5+(1)(7)
a(2) = -5+7
a(2) = 2
The second term is 2
Similarly, plug in n = 5 to get the fifth term
a(n) = -5+(n-1)(7)
a(5) = -5+(5-1)(7)
a(5) = -5+(4)(7)
a(5) = -5+28
a(5) = 23
The fifth term is 23
Finally, replace every n with 9 to find the ninth term
a(n) = -5+(n-1)(7)
a(9) = -5+(9-1)(7)
a(9) = -5+(8)(7)
a(9) = -5+56
a(9) = 51
The ninth term is 51
