# Math Help - simple equation prob...

1. ## simple equation prob...

103= 6/1+r +106/(1+r)^2

r=???

Can anyone help with this? thank you

2. Originally Posted by flynne8
103= 6/1+r +106/(1+r)^2

r=???

Can anyone help with this? thank you
Let's say $(1 + r) = x$

Then $103 = \frac{6}{x} + \frac{106}{x^2}$

[Multiply straight through with $x^2$]

$103x^2 - 6x - 106 = 0$

$x = 1.0440028316648209$

OR

$x = -0.9857504044803549$

---

$1 + r = 1.0440028316648209$

OR

$1 + r = -0.9857504044803549$

You can solve for r from there.

3. Then

[Multiply straight through with ]

Why do you multiply by?and how do do this...

Also how do you get from

to

???

Thanks

4. Why do you multiply by?and how do do this...
X squared is the common denominator. Multiply each term by x squared to simplify the equality.

5. Also how do you get from

to

???
The question you have been given is far too hard for you if you don't know how to solve a quadratic.

Janvdl applied the quadratic formula: if $ax^2+bx+c=0$ then $x = \frac {-b\pm \sqrt {b^2-4ac}}{2a}$