Order of operations 8x18/4+15

Which expression is equivalent to (3^2)^-2 a.-81 b.-12 c.1/81 d.1/12

Paul can type 60 words per minute and jennifer can type 80 words per minutes.how does paul's typing speed compare to jennifer's

Triangle abc has side lengths: ab = 3.5  cm, bc = 2.4 cm, and ac = 4.2 cmδabc ≅ δhjkwhat is the length of side hj?