Question

How many solutions does this system have? 2 x- 4 y = 8. x + y = 7.

Answer 1

2 x- 4 y = 8

x + y = 7

y= 7-x-----------(1)

2 x- 4 y = 8

on substitution

=>2x -4(7-x)= 8

=>2x -28+4x = 8

=>6x= 36

=>x= 6

From (1)

y= 7-6= 1

Therefore, the system have 1 solution

(6,1)

Answer 2

One solution: (6,1)

Explanation:

2 x- 4 y = 8

x - 2y = 4

x = 4 + 2y

x + y = 7

4 + 2y + y = 7

3y = 3

y = 1

x = 4 + 2(1)

x = 6

One solution: (6,1)