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Pearson Algebra 2 Common Core, 2011 View details

5. Quadratic Equations

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Exercise 22 Page 229

First, rewrite the equation in standard form.

x=- 2 and x=18

Practice makes perfect

To solve the equation using our calculator with a table, we first have to rewrite the equation in standard form.

x^2-16x=36

SubEqn

LHS-36=RHS-36

x^2-16x-36=0

Having rewritten the equation in standard form, we can enter it in the calculator by pushing Y= and typing it in the first row.

Next, by pushing 2ND and GRAPH, we get a table of values for whole number inputs of x. We are looking for x-values that make the y-column equal 0.

We can already see that x=- 2 provides a value of 0 in the y-column. Notice that as the x-values increase the y-values decrease. Since this is a quadratic function which opens upwards, at some point y-values must start increasing. Let's scroll down to find the second zero.

Now we can see that x=- 2 and x=18 both provide a value of 0 in the y-column. These are the zeros of the function, so the solutions to the quadratic equation are x=- 2 and x=18.

Subchapter links

Lesson Check p.229

Practice and Problem-Solving Exercises p.229-231

Standardized Test Prep p.231

Mixed Review p.231

Exercise 22 Page 229

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