The problem statement, all variables and given/known data 1. A small corporation borrowed $1,500,000 to expand it's product line. Some of the money was borrowed at 8%, some at 9%, and some at 12%. How much was borrowed at each rate if the annual interest was $133,000 and the amount borrowed at 8% was 4 times the amount borrowed at 12% 2. 2. Relevant equations 3. The attempt at a solution 1. I know you could write the total money borrowed and interest equations as a+b+c=1,500,000 .08a+.09b+.12c=133,000 However I dont know how to write the equation where the amount 'a' borrowed is 4 times the amount 'c' borrowed. 2. A. I'm not even sure how I'd start to write a system of equations for this. Something like this? x3+x4-x5+x6+x7+500=600 x1+x2-x3-x4+x5+600=500 Am I on the right track? What would you do with the constant at the end subtract it from the RHS of the equation?