Can you guys help me I’m being timed

What is the standard form of -5x^2+2x^4-11+x^3+3x

Aboat costs 19200 and decreases in value by 12% per year. how much will it cost in 5 years

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