Question 23138
Prob. #1
First, get rid of the fractions:
Multiply 1st equation thru by 3 to get:
   X + 3Y=9
Multiply 2nd equation thru by 4 to get:
  2x- Y = 4
Now multiply this last equation thru by 3 so we can get rid of the Y's.
6X -3Y = 12
This is now the equations you are working with:
1st: X +3Y= 9
2nd: 6X-3Y= 12
Now add the two equations to get:
7x = 21
 x = 3
Put this value into one of the early equations to solve for "Y".
3 + 3Y = 9
    3Y = 6 
     Y = 2
Solution: X= 3 and Y= 2
Check that answer in the original equations.

2nd Problem:
2x+5y=1
x=6y-8
Substitute this value of "x" into the 1st equation to get:
2(6y-8)+5y = 1
12y-16+5y = 1
17y = 17
  y = 1
Substitute that value into one of the original equations to get:
x=(6(1))-8
x= 6-8=2
Solution:
x = 2 and y = 1
Check that answer in the othe original equation.

Cheers,
Stan H.