One number is 9 more than twice another number. If the sum of the numbers is 129, find both numbers.

40 and 89

Step-by-step explanation:

let x be the number then the other number is 2x + 9, then

x + 2x + 9 = 129, that is

3x + 9 = 129 ( subtract 9 from both sides )

3x = 120 ( divide both sides by 3 )

x = 40

Thus the numbers are

x = 40 and 2x + 9 = 2(40) + 9 = 80 + 9 = 89

step-by-step explanation:

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.