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  1. 1Solving 7(x−2)=3x+10
  2. 2Solving a rational equation
  3. 3Solving 5−3x≤17
  4. 5Slope between two points
  5. 6Line through two points
  6. 7Slope and intercept from 3x−4y=12
  7. 8Parallel line through a point
  8. 10Solving a system by substitution
  9. 11Elimination, 2 equations
  10. 14Exponent rules, same base
  11. 15Fractional exponent, 27^(2/3)
  12. 17Simplifying root sums
  13. 20Solving 3^(x+1)=81
  14. 21Factoring x²−5x−24
  15. 23Difference of squares
  16. 24Quadratic formula
  17. 26Vertex of a parabola
  18. 27Discriminant of a quadratic
  19. 28One solution, discriminant=0
  20. 30Expanding a binomial times trinomial
  21. 31Evaluating f(-2)
  22. 34Exponential growth, 5% a year
  23. 35Half-life decay
  24. 37Solving |2x−5|=9
  25. 39Simplifying a rational expression

30Expanding a binomial times trinomial

Expand (2x−3)(x2+4x−1)\displaystyle (2x - 3)(x^2 + 4x - 1). What is the coefficient of x\displaystyle x?

The expanded form is 2x³ + 5x² − 14x + 3, so the coefficient of x is −14. You get it by distributing 2x and −3 across the trinomial, then combining the x-terms: −2x − 12x = −14x.

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