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Practice solving quadratic equations using square roots, simplifying radical expressions, and completing the square. Understand square roots, perfect squares, and irrational numbers. Examples and practice problems included.
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Do Now 4/29/19 • Take out CW/HW from last week. • Practiceworksheet 9.1 • Copy HW in your planner. • Text p. 501, #4-32 evens • Quiz Wednesday, Sections 9.1 & 9.3 A= 36 What is the area for each figure? A = 6² A= 16 A = 4² • What are the dimensions for each figure? 6 • Write an equation for area of the figure. 4 • Can you think of an equation for ONE side of the figure? 4 6
Chapter 9 “Solving Quadratic Equations” • (9.1)Simplifying Radical Expressions • (9.3)Solving Quadratic Equations Using Square Roots • (9.4) Solving Quadratic Equations by Completing the Square • (9.5) Solving Quadratic Equations Using the Quadratic Formula • (9.6) Solving Nonlinear Systems of Equations
Learning Goal SWBAT solve quadratic equations Learning Target SWBAT solve quadratic equations using square roots.
Remember This??? Section 6.2 “Radical & Rational Exponents” If b² = a then b is the square root of a. TheSQUARE ROOTof a number is denoted by the symbol , which is called aradical. radicand
Remember This??? Square Roots • All positive real numbers have two square roots, a positive and negative square root. • The symbol is read as “plus or minus” and refers to both the positive and negative square root. • Negative real numbers do not have real square roots. So there is no solution. no solution The square of an integer is called a perfect square.
Remember This??? Not PERFECT??? The square root of a whole number that is NOT a perfect square is an IRRATIONAL NUMBER. numbers that cannot be written as a quotient (fraction, ratio) of two integers and the decimal neither terminates nor repeats. To find the square root of a number that is not a perfect square estimate or use a calculator to find the square root.
Section 9.3 “Solving Quadratic Equations Using Square Roots” • To use square roots to solve a quadratic equation of the form ax² + bx + c = 0, first isolate x² on one side of the equation to obtain x² = d. Examples Solving x² = d by Taking Square Roots - If d > 0, then x² = d has two solutions: - If d = 0, then x² = d has one solution: - If d < 0, then x² = d has no solution: no solution no solution
Try It Out… No solution
Take square roots of a fraction • In cases where you need to take the square root of a fraction whose numerator and denominator are perfect squares, the radical can be written as a fraction. • For example, can be written as .
Solve the quadratic equation. Round your answer to the nearest hundredth.
A touch tank has a height of 3 feet. Its length is three times its width. The volume of the tank is 270 ft.³. Find the length and width of the tank.