Solve the equation by completing the square: x2 + 8 = 6x
Enter the smallest of the two zeros.

Question

Solve the equation by completing the square: x2 + 8 = 6x
Enter the smallest of the two zeros.

zzr0ck3r · Answer

we have x^2-6x+8 = 0

take half the middle term  so -3 and move the 8 to the RHS and add half the middle term coeffecient squared to the RHS

(x-3)^2 = -8+3^2

can you solve it from here?

anonymous · Answer

I though the 8 would be on the other side of the equal sign?

markrijckenberg · Answer

zzro0ck3r gave the right answer. This means there are not ONE, but TWO values/solutions for x.

anonymous · Answer

I know there are two values it's just confusing because I can't figure out how to do it cause apparently I'm doing it wrong

zzr0ck3r · Answer

its hard for me to explain how to complete the square on here.

note: I took half the middle term (including its sign) and said 
(x+(half the middle term))^2 and now I want only this part on the LHS so I moved the 8 to the RHS. Then you need to add half the middle term squared to the RHS. (notice the sign does not matter once you square it) then solve for x

zzr0ck3r · Answer

when I say the middle term, I mean just the coefficient.

zzr0ck3r · Answer

aslo, you want no coefficients on the 1st term so devide them away first

so if we have ax^2 + bx + c

we get

x^2+(b/a)x+(c/a)   (note: a cant equal 0)

then

(x+(b/(2a)))^2 = -(c/a)+ (b/(2a))^2 

then solve for x