Solve the system of equations using elimination by addition or by augmented matrix methods(your choice).

Show work.
x + 3y = 1
4x + 5y = 11

The augmented matrix is

[1 3 I 1]
[4 5 I 11] multiply the first row by (-4) and add to the second

[1 3 I 1]
[0 -7 I 7] divide the second row by (-7)

[1 3 I 1]
[0 1 I -1] multiply the second row by (-3) and add to the first row

[1 0 I 4]
[0 1 I -1]

The solution is x=4 and y=-1 or (4, -1)

multiply 1st eqn by 4
then we get 4x+12y=4
then reduce given 2nd eqn by this obtained eqn
7y=-7
so y=(-1)

then substitute this to the given 1st eqn;
x+ (-3)=1
x=4

so x=4 and y=(-1)