Question

1. Resolva Os Sistemas Pelo Método da Substituiçao:a) x+y=11 x-y=3b) x+y=6 2x+y=4c) 3x+y=5 2x+y=4

Answer 1

a)
{x+y=11
{x-y=3

x-y=3
x=3+y

x+y=11
3+y+y=11
3+2y=11
2y=11-3
2y=8
y=8/2
y=4

x=3+y
x=3+4
x=7

S= {7 ; 4}


b)
{x+y=6
{2x+y=4

x+y=6
y=6-x

2x+y=4
2x+6-x=4
2x-x=4-6
x=-2

y=6-x
y=6-(-2)
y=6+2
y=8

S= {-2 ; 8}


c)
{3x+y=5
{2x+y=4

2x+y=4
y=4-2x

3x+y=5
3x+4-2x=5
3x-2x=5-4
x=1

y=4-2x
y=4-2*1
y=4-2
y=2

S = {1 ;2}