What value is a discontinuity of quantity x squared plus 3 x minus 4 divided by quantity x squared plus x minus 12

What is the value of x in the following equation. -x ^3/2 = -27

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Witch represents the inverse of the function f(x)=1/4x-12