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.
Will someone please help me

Question

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. 
Will someone please help me

saifoo.khan · Answer

Discussion problems suck.

anonymous · Answer

i know... i hate em... its my final exam and im trying to get through been doing it all day

saifoo.khan · Answer

we have to use the FOIL method to multiply them on the left side of the equation.

 (x + 3)(x + 1) = 48

$$x^2+4x+3=48 $$$$x^2+4x−45$$


When we are going to solve it further by factorization, we will solve it like:

$$x^2 + 4x -45 = 0$$$$x^2 + 9x -5x -45 = 0 $$
Taking commons:

x(x+9) -5(x+9) =0

Therefore:
(x+9)(x-5)

So solutions are:
x = -9
& x = 5

anonymous · Answer

I was about to do it, got the same answer :)

saifoo.khan · Answer

LOL.

saifoo.khan · Answer

Did taht worked @87??

anonymous · Answer

what?

anonymous · Answer

yes... i got one more will u help me?

saifoo.khan · Answer

Sure, post it on left. ^.^

Dont forget to hit good answer.