1:17 i don't feel like dropping the log is more obvious than the calculations presented in the video. just because x = y implies f(x) = f(y), doesn't mean the opposite is true (but thankfully log is monotonous). and when dealing with such test questions, you can't just brush off such a notion cause then you're likely to get used to not checking other possibilities in various math problems. exam setters love to catch you off guard.
1:17 i don't feel like dropping the log is more obvious than the calculations presented in the video. just because x = y implies f(x) = f(y), doesn't mean the opposite is true (but thankfully log is monotonous). and when dealing with such test questions, you can't just brush off such a notion cause then you're likely to get used to not checking other possibilities in various math problems. exam setters love to catch you off guard.
How did -49 become -36? Or was this a transcription error?
that's not -49. it's (-4) times 9. that comes from 4ac in the quadratic formula
Nice.
Thanks!
a = 12
a=12,x=3