Question

PLEASE help with the below.

Solve the system of equations by first expressing it in matrix form as and then evaluating.


a). 3x-2y=5
4x-y =-10


b). 3x -2y =-2
4x -y = 3

Answer 1

uggghhh, matrices for such simple systems ???

anyway ....

1st one:

3 -2 5
4 -1 -10

1 1 -15 ---> #2 - #1
3 -2 5 ----> #1

1 1 -15 ---> #1
0 5 -50 ---> 3x#1 - #2

1 1 -15 ---->#1
0 1 -10 ---> #2 ÷ 5

1 0 -5 ---#1 - #2
0 1 -10 ---> #2

<b>so x = -5 and y = -10</b>
---------------------------

same thing using substitution

form #2, y = 4x+10
sub into #1
3x - 2(4x+10) = 5
3x - 8x - 20 = 5
-5x = 25
<b>x = -5 , then y = -20+10 = -10</b>

You try the second one, remember in the matrix method there is no one correct way,
what I did above just seemed like a way to me, you might have taken a different path.

Answer 2

Thank you.