Match the equation on the left to its equivalent below

Equations: y = x^2 - 6x + 16, y = (x+8) (x+11), y = x^2 - 1x - 20, y = (x + 4)^2 - 5.
Equivalents: y = (x+4)(x-5), y = (x-3)^2 + 7, y = x^2 + 19x + 88, y = x^2 + 8x + 11

1 answer

To match each equation to its equivalent, we will simplify and factor each one as needed.

  1. For \( y = x^2 - 6x + 16 \): We can complete the square or look for factorizations, but it seems simpler to check and arrive at its equivalent: \[ y = (x - 3)^2 + 7 \] This shows that the vertex form of the quadratic confirms it's equivalent.

  2. For \( y = (x + 8)(x + 11) \): Expanding this: \[ y = x^2 + 19x + 88 \] This matches with \( y = x^2 + 19x + 88 \).

  3. For \( y = x^2 - 1x - 20 \): To factor this, we look for two numbers that multiply to -20 and add to -1. We find: \[ y = (x + 4)(x - 5) \]

  4. For \( y = (x + 4)^2 - 5 \): Expanding gives: \[ y = x^2 + 8x + 16 - 5 = x^2 + 8x + 11 \]

In summary, the matches are:

  1. \( y = x^2 - 6x + 16 \) → \( y = (x - 3)^2 + 7 \)
  2. \( y = (x + 8)(x + 11) \) → \( y = x^2 + 19x + 88 \)
  3. \( y = x^2 - 1x - 20 \) → \( y = (x + 4)(x - 5) \)
  4. \( y = (x + 4)^2 - 5 \) → \( y = x^2 + 8x + 11 \)