KCarter,

Actually, the solution you give only applies to x + y = 89 ;-)

You need to learn to do matrix math.

So, enter your x coefficients in A1 and A2, your y coeff in B1 and B2, and your solution values in
C1 and C2:

1 1 89
2.15 2.4 202.35

Then select D1 AND D2, enter

=MMULT(MINVERSE(A1:B2),C1:C2)

and press Ctrl-Shift-Enter.

You will then get 45 and 44. If you had 90 in cell C1, you would get 54.6 and 35.4.

HTH,
Bernie
MS Excel MVP


"K. Carter" wrote in message
...
I need help building a formula to calculate both the "x" and "y" values for
the following equation:

x + y = 90
2.15x + 2.4y = 202.35

The solution would be x = 45 and y = 44, but I haven't found a formula that
work yet!