Answer:
all work is pictured and shown
Y = -3x - 40. Use the distributive property to get the slope and move the 10 to the other side to isolate the y

Therefore, the answer is the first choice.
(b)
A polynomial has the form

± 
+ ....
the only expression fitting this description is : x² + 2x + 7
The sum will be:
sigma(i = 1 to infinity, 30*(2/5)^i)
->

Which is equal to 30/(3/5) = 50