If PQ is parallel to ST what is ST the width of the lake?

Can someone me out here and the tell me the greatest common factor

Simplify. (-2)^-3 a. -8 b. -1/8 c. 1/8 d. 8

Aley is at the store buying some supplies for an art project. she decides to buy some colored pencils for $3.95 and a drawing tablet. the total cost of the supplies before sales tax is $6.94. what is the cost of the drawing tablet? $10.89 $2.99 $1.76 $3.01