Problema Solution
solving the equation (x + 1)(x – 2) = 4, Eric stated that the solution would be
x + 1 = 4 => x = 3
or
(x – 2) = 4 => x = 6
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.
Answer provided by our tutors
For , x-a = c or x - b = c works only if c = 0, and nowhere else. It is called the zero-factor property. To solve this equation, multiply out the left side and then write in standard form, i.e., with zero on one side.
;
;
(x - 3)(x+2) = 0;
x = 3, -2. These are the solutions to the equation.