Final answer:
To graph the equation 3y-9=-18, isolate the variable y by adding 9 to both sides and then dividing by 3. Substitute the value of y back into the original equation to check if it is a solution.
Step-by-step explanation:
To graph the equation 3y-9=-18, we need to isolate the variable y. Let's start by adding 9 to both sides of the equation to get 3y = -18 + 9, which simplifies to 3y = -9. Then, divide both sides of the equation by 3 to solve for y. This gives us y = -9/3, which simplifies to y = -3.
To check if this is a solution, substitute the value of y back into the original equation and see if it holds true. Plugging y = -3 into the equation 3y-9=-18, we get 3(-3) - 9 = -18. Simplifying this, we have -9 - 9 = -18, which is true. Therefore, y = -3 is a solution to the equation.