here I am! dunno if this is the question you meant but you haven't gotten an answer here yet.
Answer:
B) Exactly one solution. (-3.5)
Explanation:
5x + 8 - 7x = -4x + 1
combine like terms
5x - 7x + 8 = -4x + 1
-2x + 8 = -4x + 1
add 4x to both sides
-2x + 4x + 8 = -4x + 1 + 4x
2x + 8 = 1
subtract 8 from both sides
2x + 8 - 8 = 1 - 8
2x = -7
divide both sides by 2.
x = -3.5
3.5, clearly, is only one number.