Question

Determine which of the following equations, when graphed, intersect at the point (4, 0).

Select all that apply.

2 x + y = 7
x - y = 4
x + y = 4
- x - y = 4
2 x - y = 7
2 x + y = -7

Answer 1

Plug (4, 0) into each:

- 2x + y = 7 → 8 ≠ 7 (no)
- x − y = 4 → 4 = 4 (yes)
- x + y = 4 → 4 = 4 (yes)
- −x − y = 4 → −4 ≠ 4 (no)
- 2x − y = 7 → 8 ≠ 7 (no)
- 2x + y = −7 → 8 ≠ −7 (no)

So the equations x − y = 4 and x + y = 4.