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**1. Homework Statement**

Well, I am in the middle of solving a (quite difficult) differential equation using the Method of Undetermined Coefficients, and have finally come across a system of equations and I need to solve for A(sub 1), or (A1), (A2), (B1), and (B2), but I cannot figure out how to (or if it is possible at all, seeing as how I could have done the rest of the problem wrong before it). The system of equations I now have is:

(1) -7(A1) + 3(A2) + 6(B1) - 21(B2) = 2

(2) 3(A1) + 12(A2) - 7(B1) + 3(B2) = -34

(3) 21(A1) + 5(B1) = 150

**2. Homework Equations**

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**3. The Attempt at a Solution**

Using equation (3), I can determine that

(A1) = (50/7) - (5/21)(B1)

and that

(B1) = 30 - (21/5)(A1)

Using these and plugging them into equation (2), I get a 4th equation:

(4) 1029(A1) + 420(A2) - 25(B1) + 105(B2) = 5410

Now I have a new system of equations:

(1) -7(A1) + 3(A2) + 6(B1) - 21(B2) = 2

(2) 3(A1) + 12(A2) - 7(B1) + 3(B2) = -34

(3) 21(A1) + 5(B1) = 150

(4) 1029(A1) + 420(A2) - 25(B1) + 105(B2) = 5410

Now, I tried using my calculator to solve this system, but it only gives me an error. Is there another way to solve for the coefficients?? Any help would be great!