Question

which ordered pair is a solution of the equation?
y = -2x + 5
choose 1 answer:
a only (2, -9)
b only (-2, 9)
c both (2, -9) and (-2, 9)
d neither

Explanation:

Step1: Test (2, -9) in equation

Substitute $x=2$, $y=-9$ into $y=-2x+5$:
$\text{Right side} = -2(2)+5 = -4+5=1$
$\text{Left side} = -9$
$-9
eq 1$, so (2, -9) is not a solution.

Step2: Test (-2, 9) in equation

Substitute $x=-2$, $y=9$ into $y=-2x+5$:
$\text{Right side} = -2(-2)+5 = 4+5=9$
$\text{Left side} = 9$
$9=9$, so (-2, 9) is a solution.

Answer:

B. Only $(-2, 9)$