Kstands for a whole number.
k+7 is greater than 100
k-7 is less than 90
find all the numbers that k could be

If (k+7) is greater than 100, then,
k+7 > 100
k+7-7 > 100-7
k > 93

If (k-7) is less than 90, then,
k-7 < 90
k-7+7 < 90+7
k < 97

Combine the two solutions k > 93 and k < 97 to get this compound inequality: 
93 < k < 97

The number k is between 93 and 97. We are not including 93. We are not including 97.

If k is a whole number, then this is the set of possible values for k: {94, 95, 96}

94, 95, or 96

2x - 5y = 9
2x -9 = 5y
(2x -9) /5 = y

x= -1
(2(-1) -9)/5 =y
(-2 -9) / 5 = y
-11/5 = y

x=0
(0-9)/5 = y
-9/5 = y

x=1
(2(1) - 9) /5 = y
-7/5 = y