I can't understand how I can find the X's here...
(x-4)(30/x+2)=30
Thanks
Expand the brackets:Originally Posted by dgolverk
$\displaystyle
(x-4)(30/x+2)=30+2x-\frac{120}{x}-8=30
$.
Simplify a bit:
$\displaystyle
2x-\frac{120}{x}-8=0
$.
Multiply through by $\displaystyle x$:
$\displaystyle
2x^2-8x-120=0
$.
Now use the quadratic formula to solve for $\displaystyle x$
RonL
Hello,Originally Posted by dgolverk
that's what you should have done: Use the quadratic formula:
$\displaystyle x=\frac{-(-8) \pm \sqrt{64-4 \cdot 2 \cdot(-120)}}{2\cdot 2}$
$\displaystyle x=\frac{-(-8) \pm \sqrt{64+960}}{2\cdot 2}$
$\displaystyle x=\frac{-(-8) \pm 32}{2\cdot 2}$
$\displaystyle x=\frac{40}{4}\ \vee \ x=\frac{-24}{4}$
Greetings
EB