Question

Resolva os sistemas de equação:
a)x-2y=3
x+2y=7


b)x+2y=5
3x-2y=-25


c)x-10=-y
x-y=2


d)y-30=-x
x-y=10


e)2x+y=-3
-x-y=1

Answer 1

a) 2x=10
x=10/2
x=5

x-2y=3
5-2y=3
-2y=3-5
-2y=-2 (-1)
y=2/2
y=1

b) 4x=-20
x=-20/4
x=-5
x+2y=5
-5+2y=5
2y=5+5
2y=10
y=10/2
y=5

c) x+x-10=2
2x=2+10
2x=12
x=12/2
x=6

6-10=-y
-4=-y(-1)
y=4

d) -(y-30)-y=10
-y+30-y=10
-2y=10-30
-2y=-20 (-1)
2y=20
y=20/2
y=10

y-30=-x
10-30=-x
-20=-x (-1)
x=20

e) x=-2
2x+y=-3
2.(-2)+y=-3
-4+y=-3
y=-3+4
y=1