Question

usando o metodo da adição resolva a)2x+y=5
x+y=2


b)3x+6y=12
2x+6y=-10​

Answer 1

{2x+y=5 ===> y=5 -2x

{-x-y= -2

-------------- (+)

x = 3 ✓ ====> y=5 -6= -1 ✓

{3x+6y=12 ====> y=12-3x/6

{-2x-6y=+10

-------------------- (+)

x = 22 ✓ ====> y=12-66/6= -54/6= -9 ✓

Answer 2

a)

{2x+y=5

{x+y=2 ×(-1)

{2x+y=5

{-x-y=-2

x=3

x+y=2

3+y=2

y=2-3

y=-1

S={3,-1}

b)

{3x+6y=12

{2x+6y=-10 ×(-1)

{3x+6y=12

{-2x-6y=10

x=22

2x+6y=-10

2.22+6y=-10

44+6y=-10

6y=-10-44

$6y=-54 \\ y=-\frac{54}{6} \\ y=-9$

S={22,-9}