tolong jawab bsk di kumpul no 1 sampai 5

#1
y = 4x - 11
2x + y = 1
y = 1 - 2x

4x - 11 = 1 - 2x
4x + 2x = 1 + 11
6x = 12
x = 2

y = 1 - 2x
y = 1 - 4
y = -3 

#2
x + 2y = -3
2y = (-3) - x

2x - y = 4
4x - 2y = 8
2y = 4x - 8

4x - 8 = (-3) - x
4x + 3 = 8 - x
4x + x = 8 - 3
5x = 5
x = 1

y = (4x - 8) / 2
y = (-4) / 2
y = -2

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

#3
x = -1 - 2y
2x + 5y = -1
2(-1 - 2y) + 5y = -1
-2 - 4y + 5y = -1
-4y + 5y = -1 + 2
y = 1

x = -1 - 2y
x = -1 - 2
x = -3

#4
-3x = 4x + 21
-3x - 4x = 21
-7x = 21
x = -3

y = -3x
y = (-3)(-3)
y = 9

#5
Maaf yang no 5 belum pernah diajarin di sekolah XD