๐Ÿ”Ÿelementary algebra review

Ax^2+bx+c

Written by the Fiveable Content Team โ€ข Last updated September 2025
Written by the Fiveable Content Team โ€ข Last updated September 2025

Definition

The expression $$ax^2 + bx + c$$ represents a quadratic polynomial where 'a', 'b', and 'c' are constants, and 'x' is the variable. In this polynomial, 'a' determines the degree of the quadratic term, 'b' is the coefficient of the linear term, and 'c' is the constant term. Understanding this structure is essential for factoring trinomials and solving quadratic equations.

5 Must Know Facts For Your Next Test

  1. The coefficient 'a' must be non-zero for the expression to remain quadratic; if 'a' is zero, it becomes a linear equation.
  2. Factoring trinomials involves finding two binomials that multiply to produce the original quadratic expression.
  3. The discriminant, calculated as $$b^2 - 4ac$$, determines the nature of the roots of the quadratic equation.
  4. Factoring can often simplify solving quadratic equations, making it easier to find roots without using the quadratic formula.
  5. Trinomials can sometimes be factored using special patterns, such as perfect squares or difference of squares.

Review Questions

  • What steps would you take to factor a trinomial of the form $$ax^2 + bx + c$$?
    • To factor a trinomial like $$ax^2 + bx + c$$, first, identify two numbers that multiply to give you $$a imes c$$ and add up to $$b$$. Once those numbers are found, rewrite the middle term using these numbers and then group the terms into pairs. Factor out the common factors from each pair. Finally, express the factored form as a product of two binomials.
  • How does the value of 'a' in $$ax^2 + bx + c$$ affect the graph of its corresponding quadratic function?
    • The value of 'a' in the quadratic function $$f(x) = ax^2 + bx + c$$ influences the width and direction of the parabola. If 'a' is positive, the parabola opens upwards; if 'a' is negative, it opens downwards. Additionally, larger absolute values of 'a' make the parabola narrower, while smaller absolute values make it wider. This affects how steeply the function rises or falls.
  • Evaluate how understanding the factors of a trinomial like $$ax^2 + bx + c$$ can be applied to real-world problems.
    • Understanding how to factor trinomials like $$ax^2 + bx + c$$ allows us to solve real-world problems involving areas, projectile motion, and optimization scenarios. For example, in physics, finding where a projectile lands can be modeled with a quadratic equation, and factoring helps identify crucial points like maximum height or time until impact. It enhances problem-solving skills by providing methods to simplify complex situations into manageable equations that can be solved analytically.