Solve the following system of equations by substitution: 5x-y= 5 and -x+3y=13.

You are only allowed to ask 1 question at a time. I have
edited your question accordingly.

To solve a set of
equations:

a1*x + b1*y = c1 ...(1)
a2*x + b2*y =
c2 ...(2)

by substitution, we express one of the variables
in any one of the equations in terms of the other.

For
example from (1), we get x = (c1 - b1*y)/a1

This value of x
is substituted in (2)

a2*(c1 - b1*y)/a1 + b2*y =
c2

=> a2*c1/a1 - (a2*b1/a1)*y + b2*y =
c2

=> y(b2 - a2*b1/a1) = c2 -
a2*c1/a1

=> y = (c2 - a2*c1/a1)/(b2 -
a2*b1/a1)

Obtain the value of y and use it to find
x.

For the set of equations that you have to
solve:

5x - y = 5 ...(1)
-x + 3y = 13
...(2)

From (1), y = 5x -
5

Substitute this in
(2)

=> -x + 3(5x - 5) =
13

=> -x + 15x - 15 =
13

=> 14x =
28

=> x = 2

As y = 5x -
5 = 10 - 5 = 5

The solution is x = 2 and y =
5