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

x = 4, y = 0

Answer 2

So E ?

Answer 3

nope

Answer 4

2x + y = 8 (1)
x + y = 4 (2)

double equation 2 and subtract it from equation 1

2x + y = 8
- 2x +2y = 8
---------------
-y = 0

so y = 0 sub into equation 2 to find x

x = 4

Answer 5

2x + y = 8--------> 2x + y = 8

Answer 6

so answer is A

Answer 7

Alexis, keep asking. I wanna answer XD

Answer 8

yes, answer is A. this is a Didactic question, just to make sure u understand the steps in eliminating one variable. bear in mind you have to subtract (x-x, y-y) equations in order to obtain a third one with a single variable in it