Question

Resolva os sistemas:
a)x+y=9
2x+3y=23

b)x-y=10
3x+y=38

c)2x+y=0
x+3y=-10

d)x+y=20
2x+2y=40

Answer 1

A)X+Y=9------X=9-Y X=4
2X+3Y=25

2 (9-Y)+3Y=25
18-2Y+3Y=25
18-25=-Y
-5=-Y ×(-1)
5=Y

B)X-Y=10---X=10+Y X=12
3X+Y=38

3(10+Y)+Y=38
30+3Y+Y=38
4Y=-30+38
4Y=8
Y=8/4
Y=2