Use the elimination method to solve the following linear-quadratic system: Y - x^2 = x - 42 & x + y = 6

1. (-8, 14) and (6, 0)
2. (6,0)
3. (8, -2) and (-6, 0)
4. (-8, 14)

1 answer

To solve the system of equations using the elimination method, we first rewrite both equations:

  1. \( y - x^2 = x - 42 \) becomes \( y = x^2 + x - 42 \)
  2. \( x + y = 6 \) can be rewritten as \( y = 6 - x \)

Now we can set the two expressions for \( y \) equal to each other:

\[ x^2 + x - 42 = 6 - x \]

Next, we simplify this equation:

\[ x^2 + x + x - 42 - 6 = 0 \]

\[ x^2 + 2x - 48 = 0 \]

Now, we can factor the quadratic:

\[ (x + 8)(x - 6) = 0 \]

This gives us:

\[ x + 8 = 0 \quad \text{or} \quad x - 6 = 0 \]

Which leads to:

\[ x = -8 \quad \text{or} \quad x = 6 \]

Now we use these values of \( x \) to find the corresponding values of \( y \):

  1. For \( x = -8 \): \[ y = 6 - (-8) = 6 + 8 = 14 \]

  2. For \( x = 6 \): \[ y = 6 - 6 = 0 \]

Thus, the solutions to the system are:

  • \( (-8, 14) \)
  • \( (6, 0) \)

Looking at the provided answer choices, the correct answer is:

1. (-8, 14) and (6, 0)