Solve the quadratic equation by completing the square. x^2-14x+42=0 first, choose the appropriate form and fill in the blanks with the correct numbers. then, solve the equation. if there is more than one solution, separate them with commas.
form:
solution:

X^2 - 14x + 42 = 0
x^2 - 14x = -42
x^2 - 14x + 49 = 49 - 42
(x - 7)^2 = 7
x - 7 = (+-) sqrt 7
x = 7 (+-) sqrt 7

solutions are : x = 7 + sqrt 7 and x = 7 - sqrt 7

X^2-14x+42=0  subtract 42 from both sides

x^2-14x=-42  halve the linear coefficient, square it, add it to both sides, in this case: (14/2)^2=7^2=49, add 49 to both sides

x^2-14x+49=7  now the left side is a perfect square...

(x-7)^2=7  take the square root of both sides

x-7=±√7   add 7 to both sides

x=7±√7

The above is the two solutions, 7+√7 and 7-√7

I am not sure what they mean by the proper form other than perhaps the point when you have a complete square as in the point in the process where you have a perfect square...

(x-7)^2=7

the answer is C

Step-by-step explanation:

because when you just have the > without a line underneath of it the circle will be open and it will be doing up because it is the only one showing that it is greater  than 9.

Hope this helps!!!