Which of the following rewrites shows the correct process for completing the square? A. 4x^2+9x+5=0 rewritten as 4x^2+9x+81/4=-5+81/4 B. 4x^2+12x+7=0 rewritten as x^2+3x+9/4=-7/4+9/4 C. 3x^2-6x-4=0 rewritten as x^2-2x+1=4+1 D. 2x^2-8x-9=0 rewritten as 2x^2-8x+16=9+16

  B

Step-by-step explanation:

ax² + bx + c = 0 is rewritten as  x² + (b/a)x + (b/2a)² = -c/a + (b/2a)²

A) 4x² + 9x + 5 = 0    -->    x² + (9/4)x + (9/8)² = -5/4 + (9/8)²

                                        = x² + (9/4)x + 81/64 = -5/4 + 81/64

B) 4x² + 12x + 7 = 0    -->    x² + (12/4)x + (12/8)² = -7/4 + (12/8)²

                                         = x² + 3x + 9/4 = -7/4 + 9/4             < this works!

C) 3x² - 6x - 4 = 0    -->    x² + (-6/3)x + (-6/6)² = 4/3 + (-6/6)²

                                         = x² - 2x + 1 = 4/3 + 1

D) 2x² - 8x - 9 = 0    -->    x² + (-8/2)x + (-8/4)² = 9/2 + (-8/4)²

                                         = x² - 4x + 4 = 9/2 + 4