unit 3 - simplify 3x + 3 = -12x -4 isolate the variable 15x...

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NAME: _____________Joe White_______________ Student Answer form Unit 3; show all work for full credit; trial and error (guess and check) methods are not appropriate; use methods covered in class. 1. a. cuberoot(x)-5=3 Adding 5 to both sides of the equation transforms it to cuberoot(x)=8 need to multiply 8 times itself 3 times to solve 8x8x8 Answer: 512 b. Raise both sides by 2 (x^3/2)² = 27² x^3 = 729 Transpose 729 to other side,
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x^3 - 729 = 0 Factoring (x - 9)(x² + 9x + 81) = 0 Theorem: If ab=0 then either a=0 or b=0 So either x - 9 = 0 or x² + 9x + 81 = 0 (2nd expression has imaginary roots) Answer: x = 9 c. 3(x+1) = 4(-3x - 1)
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Unformatted text preview: simplify 3x + 3 = -12x -4 isolate the variable 15x = - 7 divide both sides by 15 x = -7/15 d. (x+2) - x =0-------------------------------x+2 = x^2 Again squaring both sides and making sure to check at the end for same reasons. x^2 - x - 2 = 0 Factoring (x-2)(x+1) = 0 Check x =2 and x = -1 2 works, 1 does not. . Answer: x =2 2. 1.5x/100-x a. 1.5*60/100-600 90/40 2.25 Answer: 2.25 million b. 5=1.5x/(100-x) (100-x)5 =1.5x 500-5x=1.5x 500=6.5x x=76.9 % Answer: 77% 3. a. x y-1 1 2 0.414 3 0.732 4 1 b. Because the root of a negative number will be imaginary. c. 4. a. 100 ft b. 98 ft...
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This note was uploaded on 04/07/2011 for the course ECON 101 taught by Professor Sei during the Spring '11 term at American Academy of Art.

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unit 3 - simplify 3x + 3 = -12x -4 isolate the variable 15x...

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