Question

x+2y=1
2x+3y=4 next

3m-n=5
2m+5n=7

Answer 1

1.
x + 2y = 1

x = 1 - 2y -----------------------------1
2x + 3y = 4 --------------------------2

Putting the value of x in 2

2 ( 1 - 2y ) + 3y = 4
2 - 4y + 3y = 4
-y = 2
y = -2

For x , putting the value of y in 1

x = 1 - 2y
x = 1 - 2 ( -2 )
x = 5

2.
3m - n  = 5
3m = 5 + n
m = 5 + n  --------------------1
         3

2m+5n = 7 --------------------2

Putting the value of m in 2

2 ( 5 + n ) + 5n = 7
       3
10 + 2n + 15n = 21
17n = 11
n = 11/17

For m ptting the value of n
Now do it yourself.

Answer 2

1 solution
x + 2y = 1

x = 1 - 2y -----------------------------1
2x + 3y = 4 --------------------------2

Substitute the value of x in 2 equation

2 ( 1 - 2y ) + 3y = 4
2 - 4y + 3y = 4
-y = 2
y = -2

Substitute the value of y in 1 equation

x = 1 - 2y
x = 1 - 2 ( -2 )
x = 5

2 solution
3m - n  = 5
3m = 5 + n
m = 5 + n  --------------------1
         3

2m+5n = 7 --------------------2

Putting the value of m in 2

2 ( 5 + n ) + 5n = 7
       3
10 + 2n + 15n = 21
17n = 11
n = 11/17

Substitue the value of n in 11/17 in euation 1

3m-11/17=5
51m-11/17=5
51m-11=85
51m=85+11=96
m=96/51