#1:

Let x=amount invested at 10%.

Then 3500-x is the amount invested at 15%.

The difference between the two interest rates is $85.

Also, how about showing some of your attempts instead of just posting a littany of problems.

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- Jul 31st 2006, 09:58 AM #1

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- Jul 31st 2006, 10:12 AM #2

- Jul 31st 2006, 01:27 PM #3

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Hello, Lane!

Here are a few more . . .

Solve: .

With no method specified, I'll use Elimination.

We have: .

Multiply (2) by 2: .

. . . . . . Add (1): .

And we have: .

Substitute into (2): .

Solve with Cramer's Rule: .

We have: .

. . .*No solution!*

6. Solve: .

Another trick question!

From (1), we have: .

Substitute into (2): .

Multiply by

Quadratic Formula: .

. . . . . . No real root

Therefore, the system has no real solution.