Final answer:
The equation 2 - 5b = -4b has one solution.
Step-by-step explanation:
The given equation is 2 - 5b = -4b. To determine how many solutions this equation has, we can simplify and solve for b. Subtracting -4b from both sides of the equation gives us 2 - 5b + 4b = 0, which simplifies to 2 - b = 0. Adding b to both sides gives us 2 = b. Therefore, the equation has one solution.