Quiz 4: Solving equations by factoring

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MQ5 QUEST 4A  (answers below)                                                                                 Mr. Gary Jaye

INSTRUCTIONS: 1. Express all answers in simplest form and SHOW ALL WORK.
                                   2. Solve all equations over the set of real numbers.
 

In 1 to 7, solve over the set of real numbers. SHOW STEPS and box answer. 
1. -3x3 + 90x = 21x2                          [5 pts]
 		 2. -12x2 + 60x - 75 = 0                  [5] 
 
3. 5x2 = 30x    [2]                              4. x2 + 7 = 0                [2]  

 

 5. x2 - 7 = 0               [2] 
 
6. x4 - 29x2 + 100 = 0             [5] 
 
 		 7. x4 - 4x2 = 45                  [5]
 
 

 

8. On the other side of the page, solve: 
     x2 - 5x + 2 = 0           [6] 
 
 
 		 9. On the other side of the page, use the substitution         method (U method) to solve: 
           6x2 - 11x - 10 = 0      [6] 
 
 

 

In 10 to 13, factor completely. [3 each] 
10. x2n + 2xn - 63

      

 11. 10px - 21y + 15py - 14x 
 
 
12. 3xk+2 - 15xk+1 - 42xk  
 
 		 13. 4x2 + 20x + 21
        
      

ANSWERS: 1. {0, -10, 3} 2. {5/2} 3. {0, 6} 4. Æ 5. {±Ö7} 6. {±2, ±5} 7. {±3} 8. {(5 ± Ö17)/2 }
9. {5/2, -2/3} 10. (xn + 9)(xn - 7) 11. (2x + 3y)(5p - 7) 12. 3xk(x - 7)(x + 2) 13. (2x + 3)(2x + 7)

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