Factor 27x^3 - 1i know the answer, but i really need an explanation on factoring. i can't seem to get it down.

There are several entries (examples) of "special products and factors."

x^2-y^2 = (x-y)(x+y)

x^3+y^3 = (x+y)(x^2-xy + y^2)

x^3 - y^3 = (x - y)(x^2 + xy + y^2)

The given expression, 27x^3 - 1, matches the format of the third example given above.

Note that 1 can be rewritten as 1^3 without changing its value.

Thus, The given expression, 27x^3 - 1, is the same as 27x^3 - 1^3, which in turn can be rewritten in the form x^3 - y^3:

27x^3 - 1^3 = (3x)^3 - 1^3.  And so, the factors are (3x - 1)(9x^2 + 3x + 1)

It'd definitely be worth learning and memorizing the special products and factors listed above, as well as others.

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.