a.

Question

zero

b.
No solution

c.
Unique solution

d.
Infinite number of solutions

1.
x + 9 = 8

2.
x - 8 = 2x - 8

3.
x + 3 = x + 3

4.
x - 4 = x + 3

Answer 1

a. Zero: x = -1

b. No solution

c. Infinite number of solutions

d. No solution