Step-by-step explanation:
it's my new id so you may ask questions here
Let

be an integer. Suppose there is a triangle with legs of length 16 and

. Then by the Pythagorean theorem, the length of the hypotenuse should be

The formulas for Pythagorean triples say that if the legs are integers, then so must be the hypotenuse, because if

and

are integers, then so are

,

, and

.
However,

is not a perfect square trinomial, which means for any integer

, the length of the hypotenuse is not an integer, so such a triangle doesn't exist.
I can help with number 4 we are learning this in my class to (5th grade) Its tough
the answer is b because the piggy bank originally contained $25 and the person adds $1.50 per day.. so: 25+1.5d