Question

resuelve por sustitucion

Answer 1

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

2y + 3y = 10

5 y = 10

y = 2

x = 2y = 2 *2 

x = 4

d) substituyendo  y = 2x - 5 en 4x - y :

4x - (2x -5) = 9

4x -2x + 5 = 9

2x = 9-5
2x = 4

x = 2

y = 2*2- 5 
y = 4 - 5

y = -1
 

Answer 2

x = 2y
x = 2(2) = 4

x + 3y = 10
2y + 3y = 10
5y = 10
y = 2
--------------------------
y = 2x - 5
4x - y = 9
4x - (2x - 5) = 9
4x - 2x + 5 = 9
2x = 4
x = 2

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