Question

Motoda podstawiania
1. x=1+y
x+y=5

2. y= - 8 - x
x - y=10

Answer 1

x=1+y
x+y=5

x = 1 + y

1 + y + y = 5
2y = 5 - 1
2y = 4  /:2
y = 2

x = 1 + 2
x = 3

x = 3
y = 2

----------------------------

y= - 8 - x
x - y=10

x - (-8 - x) = 10
x + 8  + x = 10
2x = 10 - 8
2x = 2    /:2
x = 1

y = - 8 - x
y = - 8 - 1
y = - 9

x = 1
y = - 9