Resolva com o método da substituição: a){x+5y=-9 3x-2y=7 b){x-4y=8 3x+2y=10 c) {x+2y=0 3x-y=7 d) {3x+y=-6 x-7y=-2 e) {x+5y=1 2x+y=11 f){3x+y=1 x+4y=-7 g){x+3y=10 5x+2y=-2 h){2x+3y=0 x-y=5 i){y-3x=0 x+2y=-1
Soluções para a tarefa
a) x+5y= -9 x= -9-5y
3x-2y= 7
3(-9-5y)-2y= 7
-27-15y-2y= 7
-15y-2y= 7+27
-17y= 34
y= 34/-17
y= -2
x= -9-5.(-2)
x= -9+10
x= 1
b) x-4y=8 x= 8+4y
3x+2y=10
3(8+4y)+2y= 10
24+12y+2y= 10
24+14y= 10
14y= 10-24
14y= -14
y= -14/14
y= -1
x= 8+4(-1)
x= 8-4
x= 4
c) x+2y=0 x= 0-2y
3x-y=7
3(0-2y)-y= 7
0-6y-y= 7
-7y= 7-0
-7y= 7
y= 7/-7
y= -1
x= 0-2(-1)
x= 0+2
x= 2
d) 3x+y=-6 y= -6-3x
x-7y=-2
x-7(-6-3x)= -2
x+42+21x= -2
22x= -2-42
22x= -44
x= -44/22
x= -2
y= -6-3(-2)
y= -6+6
y= 0
e) x+5y=1 x= 1-5y
2x+y=11
2(1-5y)+y= 11
2-10y+y= 11
-9y= 11-2
-9y= 9
y= 9/-9
y= -1
x= 1-5.-1
x= 1+5
x= 6
f) 3x+y=1 y= 1-3x
x+4y=-7
x+4(1-3x)= -7
x+4-12x= -7
x-12x= -7-4
-11x= -11
x= -11/-11
x= 1
y= 1-3.1
y= 1-3
y= -2
g) x+3y=10 x= 10-3y
5x+2y=-2
5(10-3y)+2y= -2
50-15y+2y= -2
-13y= -52
y= -52/-13
y= 4
x= 10-3.4
x= 10-12
x= -2
h) 2x+3y=0
x-y=5 x= 5+y
2(5+y)+3y= 0
10+2y+3y= 0
10+5y= 0
5y= 0-10
5y= -10
y= -10/5
y= -2
x= 5+(-2)
x= 5-2
x= 3
i) y-3x=0
x+2y= -1 x= -1-2y
y-3(-1-2y)= 0
y+3+6y= 0
7y= -3
y= -3/7
x= -1-2(-3/7)
x= -1+6/7
x= -1/7
espero ter ajudado