Perfect Square help!?

Question

Find the value of d such that

x^2-18x+d

is a perfect square.

Include how you did it plz!

Answer 1

The value of d is such that

-d=x^2-18x, therefore d=-(x^2-18x) or

d = -x^2 + 18x

Now a little trial and error, if x = +/- 1 d = 19, not a square

x = +/-2, d = 26

x = 3, d = 63

x = 4, d = 88

x = 5, d = 115

x = +/-6, d = 144  Thus a perfect square of 12

Answer 2

Using completing the square technique...

Take the number in front of the x (18 in this case).

Cut it in half (so... 9)

Then square it (so... 81)

That is the value of d.

Answer 3

Look everyone, a Zac Efron wanne-be!

Answer 4

b= -18

2b= -18

b= -18/2= -9

d= (-9)^2= 81

Answer 5

81

To complete the square, take the value to be (1/2 the value of the x-coefficient)².