Question

rozwiaz uklad rownan metoda przeciwnych wspolczynnikow :

x+2y=1 5x+9y=-2

2x-y=-3 4x-6y=38

Answer 1

a) x+2y=1 |*(-2)
2x-y= -3

-2x-4y=-2
2x-y=-3
+_________
-5y= -5 | :(-5)
y=1
y=1
x+2*1=1

y=1
x+2=1

y=1
x=1-2

y=1
x= -1
b) 5x+9y= -2 |*2
4x-6y=38 |*3

10x+18y= -4
12x-18y=114
+___________
22x=110 | :22
x=5

x=5
5*5+9y= -2

x=5
25+9y= -2

x=5
9y=-2-25

x=5
9y= -27 | :9

x=5
 y= -3