Question

resolva pelo metodo de substiçao

b)x=3y
x+2y=10

c)x+y=10
2x-y=8

d)x=2y
3x+5y=55

Answer 1

a)

x = 3y

x + 2y = 10

3y + 2y = 10

5y = 10

y = 10/5

y = 2

x = 3.2

x = 6

c)

x + y = 10

2x - y = 8

y = 10 - x

2x - (10 - x) = 8

2x + x - 10 = 8

3x = 8 + 10

3x = 18

x = 18/3

x = 6

x + y = 10

6 + y = 10

y = 10 - 6

y = 4

d)

x = 2y

3x + 5y = 55

3.2y + 5y = 55

6y + 5y = 55

11y = 55

y = 55/11

y = 5

x = 2y

x = 2.5

x = 10