Question

A) x+y=96
-x+y=16

B)3x+4y=-5
x-2y=5

obs: sistema método adição

x+y=6
2x-y=24

obs: sistema método substituição

Answer 1

A)x+y=96
-x+y=16
-----------------
2y=112
y=112/2
y=56

x+56=16
x=16-56
x=-40

Answer 2

A) x+y=96
-x+y=16
2y=112
y=112/2
y=56

x+y=96
x+56=96
x=96-56
x=40

B) 3x+4y=-5
x-2y=5 <~~~~ x=5+2y 
3(5+2y)+4y=-5
15+6y+4y=-5
15+10y=-5
10y=-5-15
10y=-20
y=-2
x=5+2y
x=5+2(-2)
x=1

C) x+y=6   
2x-y=24
3x=30
x=10
x+y=6
x+10=6
x=6-10
x=-4