Answer:
(9,21) is a solution of y=x+12
Explanation:
When is an ordered pair a solution?
To find if an ordered pair (x,y) is a solution to an equation, substitute the x-value and y-value from the ordered pair into the equation, evaluate both sides of the equation individually, and see if the equation is true.
- If the two sides are equal, the ordered pair is a solution.
- If the two sides are not equal, the ordered pair is not a solution.
Warning: A common mistake is to use the first coordinate (the x-coordinate, on the left of the ordered pair) as the value on the left side of the equation, and the second coordinate (the y-coordinate, on the right of the ordered pair), as the value for the right side of the equation. Make sure to substitute the x-value for the "x" in the equation, and the y-value for the "y" in the equation.
Going through the choices:
Point A (24,12)
y = x+12
(12) ?? (24) + 12
12 ≠ 36
not equal -- not a solution
Point B (-12,-24)
y = x+12
(-24) ?? (-12) + 12
-24 ≠ 0
not equal -- not a solution
Point C (9,21)
y = x+12
(21) ?? (9) + 12
21 = 21
equal -- (9,21) is a solution
Point D (0,-12)
y = x+12
(-12) ?? (0) + 12
-12 ≠ 12
not equal -- not a solution