Question

Resolvendo o sistema:
2x + y = 11
5x + 5y = 20

e

x + y = 11
2x + y = 20

Answer 1

a)

y = 11 -2x

5x +55 -10x = 20
-5x = -35 
x = 35/5
x = 7

y = 11 - 14
y = -3

b) y = 11 - x

2x + 11 -x = 20
x = 9

y = 11 -9
y = 2

Answer 2

1) resolva o sistema :

a)
{2x + y = 11
{5x + 5y = 20
:
{y=11-2x
{5x+5y=20
:

5x+5*(11-2x)=20
5x+55-10x=20
5x-10x=20-55
-5x= -35---->÷ambos por5
x=35/5
x=7

2x+y=11
2*7+y=11
14+y=11
y=11-14
y= -3





{x + y = 11--->(-1)
}2x + y = 20

{-x-y= -11
{2x+y 20
--------------(-)
x=9

x+y=20
9+y=2
y=2-9
y= -7