# Math Help - transpositions

1. ## transpositions

This ones beyond me!!

Make x the subject:

y=(x+4)(x+3)

if anyone can explain this one to me i would be forever grateful

2. Originally Posted by chrill911
This ones beyond me!!

Make x the subject:

y=(x+4)(x+3)

if anyone can explain this one to me i would be forever grateful
Good question!

$y=(x+4)(x+3)\Rightarrow y=x^2+7x+12$

$x^2+7x+12-y=0$

Now, use the quadratic formula...

$x=\frac{-7 \pm \sqrt{49-4(12-y)}}{2}$

$x=\frac{-7 \pm \sqrt{1+4y}}{2}$

3. Cheers for that!!!

I gotta admit i dont fully understand the quadratic formula, but it's a step in the right direction!! Time to hit the books and do some more research.....

Thanks a lot