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16. $27z^3 - 9z$ 17. $x^2 - 6x + 9$ 18. $15p^3 - 3p - 54$ 19. $x^2 - 9$…

Question

  1. $27z^3 - 9z$
  2. $x^2 - 6x + 9$
  3. $15p^3 - 3p - 54$
  4. $x^2 - 9$
  5. $8x^2 - 40x + 50$
  6. $-4x^2 - 10x + 6$

mixed practice b. factor each completely. box your answers!

  1. $9y^2 - 36$
  2. $16x^2 - 80x + 100$
  3. $-x^2 + 18x - 81$
  4. $64x^2 - 16$
  5. $\frac{1}{2}y^2 - \frac{1}{2}$
  6. $30n^2b - 87nb + 30b$
  7. $2f^2 - 16f$
  8. $12a^2 - 75$
  9. $m^4 - 1$

Explanation:

Response

Let's solve problem 16: \(27z^3 - 9z\) using factoring.

Step 1: Find the GCF

The greatest common factor (GCF) of \(27z^3\) and \(9z\) is \(9z\).
\(27z^3 - 9z = 9z(3z^2 - 1)\)

Step 1: Recognize the perfect square trinomial

The expression \(x^2 - 6x + 9\) is a perfect square trinomial of the form \(a^2 - 2ab + b^2 = (a - b)^2\). Here, \(a = x\) and \(b = 3\) (since \(2ab = 2 \cdot x \cdot 3 = 6x\)).
\(x^2 - 6x + 9 = (x - 3)^2\)

Step 1: Find the GCF

The GCF of \(15p^2\), \(-3p\), and \(-54\) is \(3\).
\(15p^2 - 3p - 54 = 3(5p^2 - p - 18)\)

Step 2: Factor the quadratic

Factor \(5p^2 - p - 18\). We need two numbers that multiply to \(5 \cdot (-18) = -90\) and add to \(-1\). These numbers are \(-10\) and \(9\).
\(5p^2 - p - 18 = 5p^2 + 9p - 10p - 18\)
\(= p(5p + 9) - 2(5p + 9)\)
\(= (5p + 9)(p - 2)\)

Step 3: Combine the factors

\(15p^2 - 3p - 54 = 3(5p + 9)(p - 2)\)

Answer:

\(\boxed{9z(3z^2 - 1)}\)

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Let's solve problem 17: \(x^2 - 6x + 9\) using factoring.