Let's solve this step by step.

You are given two equations:

1. $x = 2y - 1$
2. $y = x + 20$

You need to substitute the first equation into the second.

Step 1: Substitute $x = 2y - 1$ into $y = x + 20$.

$y = (2y - 1) + 20$

Step 2: Simplify the equation.

$y = 2y - 1 + 20$ $y = 2y + 19$

Step 3: Solve for $y$.

Subtract $2y$ from both sides:

$y - 2y = 19$

$-y = 19$

Multiply both sides by -1:

$y = -19$

Conclusion:

The correct equation resulting from the substitution is $y = -19$.

So the correct answer is D.

Do you want more details on this solution or have any questions?

Here are some related questions for further practice:

1. How would you solve for $x$ after finding $y = -19$?
2. What happens if the equation $y = x + 20$ is substituted into another equation?
3. Can you graph both equations $x = 2y - 1$ and $y = x + 20$ and find their intersection point?
4. How would the solution change if the equation was $x = 2y + 1$ instead of $x = 2y - 1$?
5. How would you approach solving the system if both equations were quadratic instead of linear?

Tip: Always check your final answer by substituting it back into the original equations to verify correctness.