Answer and step-by-step explanation:
a) -4x + 5y = -9 (2)
2x + 3y = 21
Multiply the second equation by 2, you will get:
4x + 6y = 42 (1)
Use (1) plus with (2), you will get:
4x + (-4x) + 6y + 5y = -9 + 42
11y = 33
y = 33/11
y = 3
4x + 18 = 42
4x = 24
x = 6
b) 2x + 5y = -6
3x + 2y = 2
Multiply first equation by 3, you will get:
6x + 15y = -18 (1)
Multiply the second equation by 2 and you will get:
6x + 4y = 4 (2)
Subtract (1) by (2), we got:
6x -6x + 15y - 4y = -18 - 4
11y = -22
y = -22/11
y = -2
6x + 4y = 4
6x -8 = 4
6x = 12
x = 2
c) 2x - 2y = -4
5x + 4y = 17 (2)
Multiply the first euation by 2, we got:
4x - 4y = -4 (3)
Use (3) minus for (2), we get:
4x - 5x -4y + 4y = -4 - 17
-x = -21
x = 21
4x - 4y = -4
84 - 4y = -4
-4y = -4 + 84
-4y = 80
y = 80 / -4
y = -20
d) 2x - 3y = 6
4x - 5y = 9 (1)
Multiply the first equation by 2, we got:
4x - 6y = 12 (2)
Use (1) minus for (2), we got:
4x -4x - 5y - 6y = 9 -12
-11y = -3
y = -3/-11
y = 3/11
2x - 3y = 6
2x - 9/11 = 6
2x = 66/11 + 9/ 11
2x = 75/11
x = 75/11 * 1/2
x = 75 / 22
e) x/2 + y/3 = 2
x/4 + y/3 = 4
Use the first equation subtract the second equation, we got:
x/2 - x/4 + y/3 - y/3 = 2 - 4
2x/4 -x/4 = -2
x/ 4 = -2
x = -2 * 4
x = -8
x/2 + y/3 = 2
-8 / 2 + y/3 = 2
y / 3 = 2 + 4
y/3 = 6
y = 6*3
y = 18
f) x/3 + y/2 = 3/2 (1)
x/2 + y/5 = -1/2 (2)
I don't know how to solve this, sr
Hope this helped :3