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Pearson Algebra 2 Common Core, 2011 View details

8. Graphing Radical Functions

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Exercise 71 Page 420

Use the Quadratic Formula.

9± sqrt(21)/2

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We will use the Quadratic Formula to solve the given quadratic equation. ax^2+ bx+ c=0 ⇕ x=- b± sqrt(b^2-4 a c)/2 a We first need to identify the values of a, b, and c. x^2-9x+15=0 ⇕ 1x^2+( - 9)x+( 15)=0 We see that a= 1, b= - 9, and c= 15. Let's substitute these values into the Quadratic Formula.

x=- b±sqrt(b^2-4ac)/2a

SubstituteValues

Substitute values

x=- ( -9)±sqrt(( - 9)^2-4( 1)( 15))/2( 1)

▼

Solve for x and Simplify

NegNeg

- (- a)=a

x=9±sqrt((- 9)^2-4(1)(15))/2(1)

CalcPow

Calculate power

x=9±sqrt(81-4(1)(15))/2(1)

Multiply

x=9±sqrt(81-60)/2

SubTerms

Subtract terms

x=9±sqrt(21)/2

Using the Quadratic Formula, we found that the solutions of the given equation are x= 9± sqrt(21)2. Therefore, the solutions are x_1= 9+sqrt(21)2 and x_2= 9-sqrt(21)2.

Subchapter links

Lesson Check p.418

Practice and Problem-Solving Exercises p.418-420

Standardized Test Prep p.420

Mixed Review p.420

Exercise 71 Page 420

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