Question

solve the following system of equations using matrices
4x-2y=7
7x+y=13

Answer 1

ARrgghhh, really?
Matrices for such a simple system?

ok ....

we need the inverse of
4 -2
7 1
I will assume you know how to find the inverse of a 2by2
I get
1/18 2/18
-7/18 4/18

now if we multiply that by
4 -2
7 1
we get
1 0
0 1 on left and the column matrix

33/18
3/18 on the right

so x = 33/18 or 11/6
and y = 3/18 or 1/6

OR

from the 2nd: y = 13-7x
sub into the 1st:
4x - 2(13-7x) = 7
4x - 26 + 14x = 7
18x = 33
x = 33/18 = 11/6
back into 2nd:
7(11/6) + y = 13
y = 13 - 77/6 = 1/6