## ThisShouldFeelLikeFire Group Title How exactly do I solve this equation? x2 - 12x = -36 2 years ago 2 years ago

1. kevsturge Group Title

$x^2-12x+36=0$ now solve the quadratic

2. kevsturge Group Title

gives x=6 can yuo see why

3. precal Group Title

you can use the quadratic formula or you can factor it you can also, look at its graph and see where it crosses the x axis

4. kevsturge Group Title

here yuo can factor the eqn, Do you know how to do this?

5. ThisShouldFeelLikeFire Group Title

I don't understand how you got x = 6...

6. precal Group Title

|dw:1338677027789:dw|

7. precal Group Title

|dw:1338677062779:dw|

8. ThisShouldFeelLikeFire Group Title

I'm sorry... I'm so confused. /:

9. ThisShouldFeelLikeFire Group Title

Oh! Wait I think I get it!!

10. ThisShouldFeelLikeFire Group Title

Took me a little bit :P Thank you both a ton!!

11. kevsturge Group Title

if you factorise the equation you get (x-6)(x-6) so when (x-6)=0 x=6 Do you see

12. kevsturge Group Title

Here is how I practice factorising write the factorised end point i.e. (x+3)x+4) and expand the brackets to give$x^2+4x+3x+12 \rightarrow x^2+7x+12$ now |I take $x^2+7x+12$ and work backwards because I know it will definitely factorise

13. precal Group Title

|dw:1338678477379:dw|

14. precal Group Title

|dw:1338678551861:dw|

15. kevsturge Group Title

wow that's the hard way! but it does always work. Try to factorise it before going through all this stress

16. precal Group Title

just presenting multiple ways to solve it. Quadratic formula works 100% of the time, factoring does not

17. kevsturge Group Title

that's what I said :P