Question

What is a possible first step to eliminate the variable x in the following system?
2x – 7y = 3
4x + 5y = –2

Answer 1

multiply the first equation by -2. to make it -4x+14y=-6. cancel out variable x after.

Answer 2

divide the second by -2

Answer 3

multiply the 1st equation on -2 then add both equations

Answer 4

2x – 7y = 3
4x + 5y = –2

(2x – 7y = 3)*4
(4x + 5y = –2)*2
8x-28y=12------->1
8x+20y=-8------->2
subtract 2 from 1
(8x-28y=12)-(8x+20y=-8)
8x-28y=12
-8x-20y=8
0-48y=20
24y=10
y=5/12