Answer :
A) to find x
replace y by 3x in the second equation
2y - 5x = 4
2(3x) - 5x = 4
6x - 5x = 4
1x or x = 4
To find y
y = 3x
y = 3*4
y = 12
B) to find y
x - 2y = 1
x = 2y + 1
Replace x by 2y + 1 in the first equation
2x + 3y = 9
2(2y + 1) + 3y =9
4y +2 + 3y = 9
7y + 2 = 9
7y = 7
y = 1
To find x
2x + 3y = 9
2x + 3(1) = 9
2x + 3 = 9
2x = 6
x = 3
