True, this equation is a quadratic equation,.
I'm assuming a 5-card hand being dealt from a standard 52-card deck, and that there are no wild cards.
A full house is made up of a 3-of-a-kind and a 2-pair, both of different values since a 5-of-a-kind is impossible without wild cards.
Suppose we fix both card values, say aces and 2s. We get a full house if we are dealt 2 aces and 3 2s, or 3 aces and 2 2s.
The number of ways of drawing 2 aces and 3 2s is

and the number of ways of drawing 3 aces and 2 2s is the same,

so that for any two card values involved, there are 2*24 = 48 ways of getting a full house.
Now, count how many ways there are of doing this for any two choices of card value. Of 13 possible values, we are picking 2, so the total number of ways of getting a full house for any 2 values is

The total number of hands that can be drawn is

Then the probability of getting a full house is

Answer:
b) Julie can use properties of congruent triangles to show that AB≅BC and BC≅CD. Then she can show BC≅AD because opposite sides of a parallelogram are congruent
Step-by-step explanation:
On the assumption that Julie must show all four sides to be congruent, the one remaining step after using the properties of congruent triangles is to show that side AD is congruent to the rest of the sides. Answer choice B describes that.
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IMO, Julie is finished after she shows∠A≅∠B and AB≅BC, because a parallelogram will be a square if adjacent sides are congruent (makes it a rhombus) and adjacent angles are congruent (makes it a rectangle). A rhombus that is a rectangle is a square.