Question

Por Favor Me Ajudem
a)x+y=30
x-y=4

B)x-y=3
x+2y=3

C)X-3y=6
x+3y=12

D)x+2y=8
x-2y=4
Pfv ♥♥

Answer 1

a) x + y = 30 ( x = 30 - y )
x - y = 4
30 - y - y = 4
30 - 2y = 4
- 2y = 4 -30
- 2y = - 26 ×(-1)
2y = 26
y = 26/2
y = 13
x - 13 = 4
x = 4 + 13
x = 17

b) x - y = 3 ( x = 3 + y )
x + 2y = 3
3 + y + 2y = 2
3 + 3y = 2
3y = 2 - 3
3y = -1
y = -1/3
x - 2(-1/3) = 3
x + 2/3 = 3
x = 3 - 2/3
x = 7/3

c) x - 3y = 6 ( x = 6 + 3y)
x + 3y = 12
6 + 3y + 3y = 12
6 + 6y = 12
6y = 12 - 6
6y = 6
y = 6/6
y = 1
x + 3(1) = 12
x = 12 - 3
x = 9


d) x + 2y = 8 ( x = 8 - 2y)
x - 2y = 4
8 - 2y - 2y = 4
8 - 4y = 4
- 4y = 4 - 8
- 4y = -4 x(-1)
4y = 4
y = 4/4
y = 1
x + 2(1) = 8
x = 8 - 2
x = 6