Order the steps from first to last that would be used to factor:

3x2−13x−10


(7 points)
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1 answer

To factor the quadratic expression \( 3x^2 - 13x - 10 \), here are the steps arranged from first to last:

  1. Identify the quadratic: Recognize the expression \( 3x^2 - 13x - 10 \).
  2. Multiply the leading coefficient and the constant term: Multiply \( 3 \) (the coefficient of \( x^2 \)) and \( -10 \) (the constant term) to get \( -30 \).
  3. Find two numbers that multiply to -30 and add to -13: These two numbers are \( -15 \) and \( 2 \) since \( -15 + 2 = -13 \) and \( -15 \times 2 = -30 \).
  4. Rewrite the middle term: Rewrite \( -13x \) as \( -15x + 2x \).
  5. Group the terms: Reorganize the expression as \( (3x^2 - 15x) + (2x - 10) \).
  6. Factor by grouping: Factor out the common factors in each group:
    • From \( 3x^2 - 15x \), factor out \( 3x \): \( 3x(x - 5) \).
    • From \( 2x - 10 \), factor out \( 2 \): \( 2(x - 5) \).
  7. Combine the factors: Now combine the factored groups: \( 3x(x - 5) + 2(x - 5) \).
  8. Factor out the common binomial: Factor out \( (x - 5) \): \( (x - 5)(3x + 2) \).
  9. Final result: The factored form of the quadratic is \( (x - 5)(3x + 2) \).

So the ordered steps to factor the expression are:

  1. Identify the quadratic.
  2. Multiply the leading coefficient and the constant term.
  3. Find two numbers that multiply to -30 and add to -13.
  4. Rewrite the middle term.
  5. Group the terms.
  6. Factor by grouping.
  7. Combine the factors.
  8. Factor out the common binomial.
  9. Final result.