Question

In solving the equation (x + 4)(x – 7) = -24, Eric stated that the solution would be
x + 4 = -24 => x = -28
or
(x – 7) = -24 => x = -17
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 1

this sound like it was written by a math teacher.
if the product of two numbers is -24 you have no idea what the two numbers are. one is z, the other is \[\frac{-24}{z}\]
if you want to solve this quadratic, you must multiply out and collect terms, set = 0 and solve.

Answer 2

Yep, Eric messed up, he did not solve the problem.

Answer 3

\[(x+4)(x-7)=-24\]
\[x^2-3x-28=-24\]
\[x^2-3x-52=0\]
etc

Answer 4

that is wrong it would be
x^2 -3x -4=0

Answer 5

yes you are right and i am wrong
makes it much easier

Answer 6

lol satellite

\[x^2 - 3x - 28 = -24\]
\[x^2 - 3x -4 = 0\]