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3-5-15
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    The first thing we're going to do with this equation is define our variables. So let X equal the amount at 8%, Y equal the amount at 6%, and Z equal the amount at 9%. So we know that X + y + Z has to equal 93,000 and the interest .0 eight X + .06 Y plus .09 Z has got equal 7110. It also tells us the interest or the .08 X of the first one is three times the interest of the third one so or the second one so 3 * .06 Y. Taking all the variables to one side, in that third equation we get .08 X equaling -.18 Y equaling 0. So the fact that the third equation doesn't have AZ in it means I'm going to combine one and two to eliminate the ZI get a new equation negative .0 One X -, .03 Y equaling negative 1260. So now I'm going to combine equations 3:00 and 4:00 because they each only have X&Y, and I end up with Y equaling 24,000. If we substitute Y into equation three or four because they each have two variables and we've now solved for one variable, we get X equal 54,000. So now we have 2 variables. So we're going to look for an equation with three variables in order to solve for the last one. So we're going to substitute into one or two and we get Z equal 15,000. I'm going to leave it to you to do the check and to write the answer in words.