# assignment sheet-WA9_MAT-115-mar18 (1).docx - MAT-115...

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MAT-115: INTERMEDIATE ALGEBRA Written Assignment 9 9.1: Solve Quadratic Equations Using the Square Root Property Solve. 1. x 2 = 25 x=±5 2. x 2 + 25 = 0 x 2 = -25 x= 25 i ± 5i 3. x 2 = 20 x= ± 2 5 4. 3 x 2 = 27 x 2 =9 x=3, -3 5. ( x 2 ) 2 = 36 x-2=±6 x= -4, 8 6. ( x + 5 ) 2 =− 49 x+5=± 49 x + 5 = ± 7 i x = 7 i 5 x = 7 i + 5 7. x 2 + 6 x + 9 = 4 (x+3) 2 =4 x+3=±2 x=-5 x=-1 8. ( x + 5 ) 2 20 =− 4 (x+5) 2 =16 x+5= 16 x+5=±4 x=-9 x=-1 9.2: Solve Quadratic Equations by Completing the Square Complete the square to make a perfect square trinomial. 9. x 2 + 14 x x 2 +14x+49 10. x 2 2 x x 2 -2x-1 Solve by completing the square. 11. x 2 20 x = 44 X 2 -20x+100=44+100 (x-10) 2 =144 x-1-=± 144 x-1=±12 x= 13 x = ¿ -11 12. x 2 2 x = 3 X 2 -2x+1=4 (x-1) 2 4 x-1=±2 x=3 x=-1 Copyright © 2018 by Thomas Edison State University. All rights reserved.
13. x 2 8 x + 12 = 5 x 2 -8x+16 =-7+16 x 2 -8x+16=9 (x-4) 2 =9 x-4=±3 x=7 x=- 1 9.3: Solve Quadratic Equations Using the Quadratic Formula Solve by using the quadratic formula. . x = b 2 4 ac 2 a 14. 2 x 2 + 5 x 3 = 0 x = 5 ± 5 2 4 ( 2 )(− 3 ) 2 ( 2 ) x= 5 ± 25 + 24 4 x= 5 ± 7 4 x= 12 4 x=-3 X= 2 4 x= 1 2 , x=-3 15.