Question

Which ordered pair is a solution of the equation? y=-2x+5y=−2x+5 (Choice A) A Only (2,-9)(2,−9) (Choice B) B Only (-2,9)(−2,9) (Choice C) C Both (2,-9)(2,−9) and (-2,9)(−2,9) (Choice D) D Neither

Answer 1

The correct answer is B. Only (-2,9) is a solution of the equation.

Explanation:

To figure out if an ordered pair is a solution to an equation, you could perform a test.

Identify the x-value in the ordered pair and plug it into the equation. When you simplify, if the y-value you get is the same as the y-value in the ordered pair, then that ordered pair is indeed a solution to the equation.

We have the equation

`y=-2x+5`

and two different ordered pairs (2, -9) and (-2, 9).

We use the x-value in the first ordered pair, x = 2, and we plug it into the equation.

`y=-2(2)+5\\y=-4+5\\y=1`

If we compare with the ordered pair (2, -9), y must be equal to -9, but when we plugged x = 2 into the equation, we obtained that y = 1, so this is not a solution.

Using the x-value of the second ordered pair, x = -2, we get

`y=-2(-2)+5\\y=4+5\\y=9`

Because we obtained y = 9, when we plugged x = -2, the ordered pair (-2, 9) is a solution of the equation.

The correct answer is B. Only (-2,9) is a solution of the equation.

Answer 2

Choice B: Only (-2, 9)

Explanation:

Of the two choices, only the point (-2, 9) satisfies the equation:

... y = -2x +5

... 9 = -2(-2) +5 = 4 +5 = 9