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McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

Study Guide and Review

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Exercise 22 Page 217

Recall that sqrt(- a)= isqrt(a).

± sqrt(5)i

Practice makes perfect

To solve the given equation, let's first isolate x^2.

3x^2+15=0

LHS-15=RHS-15

3x^2=- 15

.LHS /3.=.RHS /3.

x^2=- 5

We cannot find any real square roots of a negative number, so we will need to use the fact that sqrt(- a)= isqrt(a) to solve for x.

x^2=- 5

sqrt(LHS)=sqrt(RHS)

x=± sqrt(- 5)

sqrt(- a)= isqrt(a)

x=± i sqrt(5)

CommutativePropAdd

Commutative Property of Addition

x=± sqrt(5)i

Subchapter links

1 Solving Quadratic Equations by Factoring p.217

2 Complex Numbers p.217

3 The Quadratic Formula and the Discriminant p.218

4 Transformations of Quadratic Graphs p.218

5 Quadratic Inequalities p.219

Practice Test p.219