Factoring vs. original equation

[stnbtch15]

ok so i was presented with the equation x^2-7x+12=0 and i can't decide what the answer should be. if i factor the equation i come up with 3 and 4. but when i plug those back into the original equation it doesn't work. so does that mean that there is no answer or does it mean I'm doing something wrong?

 

[Mentallic]

It means you're calculating the values you plugged back into the equation incorrectly

3 and 4 are the correct answers, so try plugging them in once more, and if you still aren't getting zero after plugging in those values, post what you've done so we can help show you what you've done wrong (even if you used a calculator, show us exactly how you wrote it in the calculator because the misuse of brackets can screw up a lot of people).

 

[stnbtch15]

well now i feel like a dummy

 

[Mentallic]

Happens all the time - but... you don't... do it all the time do you?

Haha good luck with those quadratics

 

[Phrak]

Um. You mean -3 and -4.

 

[Mentallic]

Phrak, best you go back and revise your quadratics as well

 

[Mark44]

I agree. The OP arrived at the correct solutions, but made a mistake in checking them.

 

[Phrak]

Phrak, best you go back and revise your quadratics as well

Oh my! You got me.