4)
x + 5 < 14
Subtract 5 on both sides
x + 5 - 5 < 14 - 5
x < 14 - 5
x < 9
Answer is D.
5)
< (less than) and > (greater than) have empty circles because the number is not included.
For example, x > 5
5 is not a solution because we are looking for all x that is greater than 5.
≤ (less than or equal to) and ≥ (greater than or equal to) have a closed circle because the number is included.
For example, x ≤ 7
7 is a solution because we are looking for all x that is less than or equal to 7.
Answer is C.
6)
4(x-1) ≥ 8
Divide 4 on both sides
(x-1) ≥ 2
Add 1 on both sides
x ≥ 3
Answer is D.