Question

The ordered pair (-1, 4) is a solution to which of the pairs of equations? (1)

(1) y = -x + 3, y = x + 1
(2) x - y = 2, x + y = - 6
(3) x + y = - 2, 7x - 4y = 8
(4) y = -x + 3, y = 2x + 6

Answer 1

d

Explanation:

Substitute x = -1 into the equations. If the solution is y = 4 for both, then (-1, 4) is the solution.

(a) y = 1 + 3 = 4

y = -1 + 1 = 0

(b) -1 - y = 2 ⇒ y = -3

-1 + y = -6 ⇒ y = -5

(c) -1 + y = -2 ⇒ y = -1

7(-1) - 4y = 8 ⇒ y = -15/4

(d) y = 1 + 3 = 4

y = 2(-1) = 6 = 4