# algbera

posted by
**kozy**
.

In solving the equation (x + 3)(x + 1) = 48, Eric stated that the solution would be

x + 3 = 48 => x = 45

or

(x + 1) = 48 => x = 47

However, at least one of these solutions fails to work when substituted back into the original equation. Why is that? Please help Eric to understand better; solve the problem yourself, and explain your reasoning.