Answer:
Step-by-step explanation:
1. 5x + 9 = 9 + 5x
Ans: Infinitely many solutions.
2. -4z + 8 = -4z - 8
Add 4z to both sides
-4z + 4z + 8 = -4z + 4z - 8
8 ≠ -8
Answer: No solution
3. z -3 = 3 -z
Answer: No solution
4) 3x + 7 = 7x +3
Subtract 3x from both sides
3x - 3x + 7 = 7x - 3x + 3
7 = 4x + 3
Subtract 3 from both sides
7 - 3 = 4x - 3
4 = 4x
Divide both sides by 4
4/4 = 4x/4
1 = x
Answer: One solution
