8.
[tex]40+105+x=180\\
x=35[/tex]
9.
The sum of two sides must be greater than the third side.
It can't be 5 because [tex]5+5=10\not>12[/tex].
It can't be 7 because [tex]5+7=12\not>12[/tex].
It can't be 17 because [tex]5+12=17\not>17[/tex].
So it's 12.
10.
a. Turk, McAllister
b. Market, Mission, Howard
c. not sure about this one
