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Graphing Quadratic Equations: example 10.44 · Physics Playground

Exercises Roots and quadratic equations

Example 10.44 from Elementary Algebra, 10.5 Graphing Quadratic Equations

Graphing Quadratic Equations: example 10.44

Determine whether each parabola opens upward or downward:

ⓐ $y = −3 x^{2} + 2 x - 4$ ⓑ $y = 6 x^{2} + 7 x - 9$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Solution

ⓐ
Find the value of "a".
Since the “a” is negative, the parabola will open downward.

ⓑ
Find the value of "a".
Since the “a” is positive, the parabola will open upward.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Determine whether each parabola opens upward or downward:

ⓐ $y = 2 x^{2} + 5 x - 2$ ⓑ $y = −3 x^{2} - 4 x + 7$

How did it go?

PreviousGraphing Quadratic Equations: example 10.43 Next Graphing Quadratic Equations: example 10.45

From Elementary Algebra (1st edition) by OpenStax (Rice University), section 10.5, licensed under CC BY 4.0. Original at openstax.org. We split the solution into steps; the words, numbers and figures are the book's. OpenStax doesn't endorse this site.

ⓐ Find the value of "a".		Since the “a” is negative, the parabola will open downward.
ⓑ Find the value of "a".		Since the “a” is positive, the parabola will open upward.

Solution

Your turn