Question

elimination was used to solve a system of equations. one of the intermediate steps led to the equation 2x= 8. which of the following systems could have led to this equation?

Answer 1

9514 1404 393

Answer:

C

Explanation:

The step shown indicates that y was eliminated from the equations. For choices A, B, D, this is done by adding the equations together (the y-coefficients are opposites). The result of doing that gives x-terms of 4x, 0x, and 0x, respectively. These x-terms do not match the one given: 2x.

For choice C, the y-term is eliminated by subtracting twice the second equation from the first. Doing that gives ...

(4x +2y) -2(x +y) = (14) -2(3)

4x +2y -2x -2y = 14 -6 . . . . eliminate parentheses

2x = 8 . . . . . . . . . . . . . . collect terms