Question

1). Solve 3x-y=7 and 3x+y=11 using elimination method

2). Solve 3x+y=9 and 4x-y=-14 using elimination method

Answer 1

Explanation:

3x-y=7 ...(1)

3x+y=11 ...(2)

add

6x=18

x=18/6=3

subtract (1) from (2)

3x+y-3x+y=11-7

2y=4

y=4/2=2

(2)

3x+y=9 ...(1)

4x-y=-14 ...(2)

add

7x=-5

x=-5/7

from (1)

3(-5/7)+y=9

-15/7+y=9

y=9+15/7=(63+15)/7=78/7