# nid Help on determining A, B, C, and D T_T

• Sep 29th 2006, 07:03 AM
nid Help on determining A, B, C, and D T_T
6 = 2A + 4C
-15 = -9A + B - 12C + 4D
9 = 12A - 4B + 9C - 4D
3 = -4A + 4B - 2C + D

I just need any possible method to solve this problem
• Sep 29th 2006, 07:22 AM
earboth
Quote:

6 = 2A + 4C
-15 = -9A + B - 12C + 4D
9 = 12A - 4B + 9C - 4D
3 = -4A + 4B - 2C + D
I just need any possible method to solve this problem

Hello,
I don't know which method you know to solve a system of linear equations. So I'm going to show you, how I solve this system:
1. From the 1rst equation you get: a = 3-2C
Plug in this term instead of a in the remaining 3 equations. After a little bit of simplifying you'll get:
b+ 6c+4d = 12
-4b-15c-4d = -27
4b+ 6c+ d = 15

2. From the 1rst equation you get: b = 12-6c-4d
Plug in this term instead of b in the remaining 2 equations. After a little bit of simplifying you'll get:

9c + 12d = 21
-18c-15d = -33

This system is easy to solve. I'll leave it up to you.

The final result is (a,b,c,d) = (1, 2, 1, 1)

Greetings

EB