What is equivalent to 0 = 2x2 - 16x – 18 when completing the
square?

x = 1

x = -9

Step-by-step explanation:

(2x2 +  16x) -  18  = 0

2x2 + 16x - 18  =   2 • (x2 + 8x - 9)

x2 + 8x - 9

 -9    +    1    =    -8

     -3    +    3    =    0

     -1    +    9    =    8

 2 • (x + 9) • (x - 1)  = 0

2   =  0

x+9 = 0  

x = -9

x-1 = 0

x = 1

x2 + 8x - 9  = 0

  x2+8x = 9

(x+4) • (x+4)  =

 (x+4)2

x2+8x+16 = 25 and

  x2+8x+16 = (x+4)2

(x+4)2 = 25

x = -4 + √ 25

 x2 + 8x - 9 = 0

has two solutions:

 x = -4 + √ 25

  or

 x = -4 - √ 25

           - B  ±  √ B2-4AC

 x =   ————————

                     2A

A   =     1

                     B   =    8

                     C   =   -9

B2  -  4AC   =

                    64 - (-36) =

                    100

 -8 ± √ 100

  x  =    —————

                   2

  x  =  ( -8 ± 10) / 2

x =(-8+√100)/2=-4+5= 1.000

or:

x =(-8-√100)/2=-4-5= -9.000

 x = 1

x = -9

answer: domain and range mean all possible values of x and y that could be substituted to the inequality. a solution means all possible values that make the inequality statement true. so while the range is still all real numbers, the solution is the shaded area, for which y will always be greater than the line of the function.