Someone please help?! Which of the following is a complex number?

-4+ square root 7/3

4/ square root 3 - 7 square root 3/5

5/2 - square root 15

2/3 + square root - 27/28

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?

Solve for n? [tex]z = \frac{3}{4} mn[/tex]

The figure shows triangle def and line segment bc, which is parallel to ef: triangle def has a point b on side de and point c on side df. the line bc is parallel to the line ef. part a: is triangle def similar to triangle dbc? explain using what you know about triangle similarity. part b: which line segment on triangle dbc corresponds to line segment ef? explain your answer. part c: which angle on triangle dbc corresponds to angle f? explain your answer. asap