Question

Help me with completing the square for my h.w.

Answer 1

1. your leading coefficient has to be 1 (nothing before the x^2). If there is you have to divide that out before you start.
2. Move your constant (the number without any x attached) to the other side of the equation
3. take 1/2 of the b term (the one with the x attached) and then square it and then add it to both sides
4. Factor the left side
5. Set each factor equal to 0 and solve

Here is an example:

4x^2-24x+20=0
The first term is not a 1 so we have to divide it out by 4 first
x^2-6x+5=0
Move the 5 to the other side.  It becomes negative.
x^2-6x=-5
Take 1/2 of 6 (3) then square it (9) and add it to both sides.
x^2-6x+9=-5+9
Factor the left side
(x-3)(x-3)=4
(x-3)^2=4
To solve you need to square root both sides
x-3=+/-
x-3=+/-2
x=3+2=5
x=3-2=1
Those would be your two answers.

Hope that helps