Question 890227: Consider the following system of equations.
ax+by=1+a
3ax+2by=-2+b
If the solution to the above system is (– 1, 3), find the values a and b.
Answer by richwmiller(17219)   (Show Source):
You can put this solution on YOUR website! plug in -1 for x and 3 for y
-a+3b=1+a
-2a+3b=1
-3a+6b=-2+b
-3a+5b=-2
-2a+3b=1
-3,5,-2
-2,3,1
determinant = 1
a= -11/1 = -11
b = -7/1 = -7
-3,5,-2
-2,3,1
divide row 1 by -3/1
1,5/-3,-2/-3
-2,3,1
add down (2/1) *row 1 to row 2
1,5/-3,2/3
0,1/-3,7/3
divide row 2 by 1/-3
1,5/-3,2/3
0,1,-7
We now have the value for the last variable.
We will work our way up and get the other solutions.
add up (-5/-3) *row 2 to row 1
1,0,-11
0,1,-7
final
1,0,-11
0,1,-7
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