Question

In the function f(x) = 4(x2 − 6x + ____) + 20, what number belongs in the blank to complete the square?

Answer 1

Please help

Answer 2

The square of half the coefficient of x. (-6/2)² = 9

Answer 3

so???

Answer 4

Thats the answer???

Answer 5

9 is the answer

Answer 6

oh ok

Answer 7

can u show me the work

Answer 8

i wanna see how u got it

Answer 9

one moment

Answer 10

k

Answer 11

so to complete the square you take half the coefficient of the 'x' which is 6...so 3...then square it....so 9....and add it to both sides.

Answer 12

ok thx

Answer 13

An equation of the form \[ax^2+bx+c=0\] can be written in completed square form as \[a(x+d)^2+e=0\] where \[d=\dfrac{b}{2a}\]\[e=c-\dfrac{b^2}{4a}\]. You have b=-24 and a=4, so d=-24/(2*4)=-24/8=-3. In your question they have the brackets expanded, so we just need to expand the brackets: \[4(x-3)^2+...=4(x^2-6x+9)+...\] (I've omitted the rest as it has no effect on the brackets and you only need to find one number, not the whole lot.