How do you solve #7x-y=44# and #x+4y=27# by elimination?

1 Answer
Feb 14, 2017

Answer:

Not sure what you mean by "elimination" but I do it this way.....

Explanation:

First, #7x - y = 44# therefore #7x = 44 + y# and #x = (44 + y) / 7#
Also, #x + 4y = 27# therefore #x = 27 -4y#

Therefore #44 + y = 7.(27 - 4y)#
And therefore #44 + y = 189 -28y# by multiplying out the bracket.
So #y + 28 y = 189 -44#
And #29 y = 145#
Therefore #y =145/29= 5#.

And we already know that #x = 27 - 4y#
So substituting in y we get #x = 27 - (4.5) = 27 -20 = 7#.