Find the solution set

Problem in comments

Question

Find the solution set

Problem in comments

anonymous · Answer

$$\LARGE x^2+14x+49=0$$

@mathmale

mathmale · Answer

Aha:  a factoring problem.  Which of the following methods are you most comfortable with?  (a) direct factoring based on the knowledge that 49 factors out to 7*7 or (-7)(-7); (b) quadradic formula, (c) graphing; (d) completing the square?
We could go through any of those; your choice.

anonymous · Answer

A seems to be the easiest, or is there an easier method? =]

mathmale · Answer

(a) is the easiest, yes!  :)
Think:  x^2 + 14x + 49 = two binomial (two-term) factors, each with x and each with 7 in it:  (x+7)(x+7).
You can check the correctness of this result by using the FOIL method to multiply out (x+7)(x+7).

mathmale · Answer

This is a relatively easy problem.  If you'd like to discuss a harder one, then by all means post it.

anonymous · Answer

So the solution set is {7,7}?

anonymous · Answer

Never mind, it's -7 :D. Thanks! :)

mathmale · Answer

Actually, you were right the first time:  The solution set is indeed {7, 7}.  You have TWO solutions which happen to be identical.  (That's OK.)

anonymous · Answer

Oh it just told me "-7" was correct and {7,7} was not correct O_o strange?