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## Do Now 5/10/11

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**Do Now 5/10/11**• Take out HW from last night. • Text p. 456, #16-40 evens • Copy HW in your planner. • Text p. 456, #42-64 evens • Quiz sections 9.1 & 9.2 Friday • In your journal, solve the following equations.**16) ±5**18) ±9 20) ±32 22) ±40 24) 7 feet 26) -11 28) ±4 30) ±16 32) -3 34) -3.2 36) 10.5 38) 36.4 40) 2.6 Homework Text p. 456, #16-40 evens**Objective**• SWBAT simplify expressions with radicals and solve equations using square roots**Section 9.1 “Square Roots”**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**Evaluate the Expression**√ a – b a = 48, b = 12 √ 48 – 12 PEMDAS √ 36 6**Evaluate the Expression**-3√ ab a = 48, b = 12 -3√ (48)(12) PEMDAS -3√ 576 -3(24) -72**Try it out…Evaluate the Expression**a = 11 b = 5 a = 3 b = 7**Solve Equations Using Square Roots**To solve an equation with an x², you need to ISOLATE the x² on one side and then take the square root of both sides of the equation. If then If then**Equation**Remember this? 2 s + 8 = 20 Left side Right side ‘s’ has to be 6 in order to make the equation balanced. Like a scale, the left side and right side must be the same in order to be balanced!**Equation-**Remember this? • mathematical sentence with an equal sign Like a scale, both sides must be EQUAL in order to be balanced.**Solving Equations with x²…**Isolate the variable! Get ‘x²’ by itself. x² + 5 = 21 To get the ‘x²’ by itself first get rid of “adding 5.” • 5 • 5 Do the opposite. “Subtract 5.” Whatever you do to one side of the equation you must do the other side. x² = 16 √ √ To get the ‘x’ by itself get rid of the “square” by using the square root. x = ±4**Solving Equations with x²…**3x² - 7 = 18 +7 +7 3x² = 25 3 3 √ x² = 8.3 √ x = ±2.9