How many subsets of at least one element does a set of six elements have

In trapezoid efgh, m∠hef=(4x2+16)∘ and m∠gfe=(5x2+12)∘. find the value of x so that efgh is isosceles. i'm desperate.

An apartment has a replacement cost of $950,000 and contents valued at $1,450,000. it has a classification of a and a territory rating of 3. find the annual premium a) $10,185 b) $9,230 c) $3,155 d) $13,830

Two cyclists 84 miles apart start riding toward each other at the samen time. one cycles 2 times as fast as the other. if they meet 4 hours later what is the speed (in miles) of the faster cyclists