Hi Spor7tdardLamilokab, this particular equation is a binomial probability equation:

P(X) = 

( frac{n}{k})  * p^{k} *(1 - p)^{n-k}

Note that it’s not n / k, but rather the notation is n choose k. Brainly software will not allow me to do this, but imagine the n choose k, without the bar, and that the correct notation.
 
Where  (frac{n}{k}) equals   frac{n!}{k!(n-k)!} , where n! is n * (n-1) * (n-2) 8 … 1

So for your particular equation:

P(x geq 3) =  (frac{5}{3}) * 0.52^{3} * (1 - .52)^{5-3}

You would repeat the above equation for 4 as well and add that to the computation for 3, since you want the probability that you’ll get 3 or more heads.

Solving this produces the answer:

P(x geq 3) = 0.34308352

You can also solve this with a TI 83 or 84.

To do this, the steps are 2ND | VARS (or DISTR) | BINOMPDF| TRIALS | PROBABILITY | X VALUE

Doing this for 3 and 4 produces the same result:

binompdf(4, 0.52, 3) + binompdf(4, 0.52, 4) = 0.34308352