Cheerios 3.68 for 17 oz vs apple jacks 2.98 for 13 oz

How to do this , and can some one explain

Ill mark the brainliest if you me with the these three questions 7,8,9

Which function in vertex form is equivalent to f(x) = x2 + 6x + 3? f(x) = (x + 3)2 + 3 f(x) = (x + 3)2 − 6 f(x) = (x + 6)2 + 3 f(x) = (x + 6)2 − 6