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5.3 Solving Quadratic Equations by Finding Square Roots. (p. 264) By: L. Keali’i Alicea. How would you solve the equation: x 2 = 4 (take the square root of each side!). * Remember, the square root of a positive # has 2 answers! (one + and one -). Radical. Radical sign. Radicand.
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5.3 Solving Quadratic Equations by Finding Square Roots (p. 264) By: L. Keali’i Alicea
How would you solve the equation:x2 = 4(take the square root of each side!) * Remember, the square root of a positive # has 2 answers! (one + and one -)
Radical Radical sign Radicand
Properties of Square Roots (a>0 and b>0) • Product Property – • Quotient Property- Example: Example:
Examples 1. 2. 3.
Rationalizing the Denominator You CANNOT leave a radical in the denominator of a fraction! No tents in the basement!!!! (the numerator is OK) Just multiply the top & bottom of the fraction by the radical to “rationalize” the denominator.
More Examples! 1. 2. Can’t have a tent in the basement!
Solving Quadratic Equations • Solve. 3(x-2)2=21 • Solve. 3 - 5x2 = -9 -3 -3 -5x2 = -12 -5 -5 x2 = 3 3 (x-2)2 = 7
More Examples! 4. Solve. • Solve. 4x2-6=42 +6 +6 4x2=48 4 4 x2 = 12
Falling Objects! • Use h = -16t2 + h0 Height of the object after it has fallen Object’s initial height # of seconds after the object is dropped
Example • The tallest building in the USA is in Chicago, Illinois. It is 1450 ft. tall. How long would it take a penny to drop from the top of the building to the ground?