I know that this is fairly simple,

but I forgot how to do this so could you please help me??

Are there any specific steps that you have to take?? (Thinking)

7x+2y= -28

and

21d*d+85d-26=0

If you can help me that would be really great.

Thank you

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- Jun 8th 2008, 02:49 AMsweetcitruCan you explain to me how to do this?
I know that this is fairly simple,

but I forgot how to do this so could you please help me??

Are there any specific steps that you have to take?? (Thinking)

7x+2y= -28

and

21d*d+85d-26=0

If you can help me that would be really great.

Thank you - Jun 8th 2008, 02:55 AMjanvdl
The first one cannot be solved unless you have another expression. It must be solved by simultaneous equations.

For the second one:

$\displaystyle 21d^2 + 85d - 26 = 0$

You'll need to factor out here.

$\displaystyle (3d + 13)(7d - 2) = 0$

Thus:

$\displaystyle 3d = -13$

$\displaystyle d = \frac{-13}{3}$

OR

$\displaystyle 7d = 2$

$\displaystyle d = \frac{2}{7}$