Question

2x - y = 8
x + 2y = 4
For the system of equations above, what is the value
of x + y​

Answer 1

A) 2x - y = 8

B) x + 2y = 4 We multiply A) by two

A) 4x -2y = 16

B) x + 2y = 4 then add the equations

5x = 20

x = 4

(then we put 4 into B)

4 + 2y = 4

2 y = 0

y = 0

Explanation:

Answer 2

x + y = 4

Explanation:

2x - y = 8 | ×1 |

x + 2y = 4 | ×2 |

2x - y = 8

2x + 4y = 8

__________--

-5y = 0

y = 0/-5

y = 0

2x - y = 8

2x - 0 = 8

2x = 8

x = 8/2

x = 4

x + y

= 4 + 0

= 4