Question

Using elimination to solve the system 2x + y = 8 and x + y = 4, which of the following could be the first step?

A. 2x + y = 8--------> 2x + y = 8
(x + y = 4)(-1)---> -x - y = -4
B. 2x + (4 - x) = 8
C. 2x + y = x + y
D. 3x + 2y = 12
E. x = 4

Answer 1

Answer: the option A.

The elimination method consist is adding the two equations in a way that one variable be eliminated..

In order to do that you might have to manipulate on of the equations prior to add the two equations.

In this case, ff you multiply the second equation by - 1 you will get

- x - y = - 4

which you can add to the first equation

2x + y = 8 to eliminate the y.