Substitute the y=1:
2x + 5(1) = 9
2x + 5 = 5
subtract the 5:
2x = 4
Divide by 2:
x = 2
Do you have the numbers? if you do then add them together
This is an example of a set defined by describing the property of its elements: every element in the set must be an integer, greater than or equal to -6, and less than zero (ecluded).
So, all the numbers that satisfy this requests are -6,-5,-4,-3,-2,-1, and the answer is thus b.