Answer:
To find the unknown value in the proportion (2x + 1) / 2 = (x + 2) / 5, we can cross-multiply the terms on the left-hand side and the right-hand side to eliminate the fractions. This gives us the equation 2(2x + 1) = 5(x + 2), which simplifies to 4x + 2 = 5x + 10. Subtracting 4x from both sides of the equation, we get 2 = x + 10, which can be rewritten as x = -8. Therefore, the unknown value in the proportion is x = -8.
Explanation: