find the zeros of the function by completing the square
f(x)=x^2+18x
a. x=-72;90
b. x=-18;0
c. x=-90;72
d. x=0;18
To find the zeros of the function by completing the square, we will first rewrite the function f(x) = x^2 + 18x as a completed square form.
f(x) = x^2 + 18x
f(x) = (x^2 + 18x + 81) - 81
f(x) = (x + 9)^2 - 81
Now, to find the zeros of the function, we set f(x) = 0:
0 = (x + 9)^2 - 81
81 = (x + 9)^2
±√81 = x + 9
x = -9 ± 9
x = -18, 0
Therefore, the zeros of the function are x = -18, 0. So, the correct option is:
b. x = -18; 0