What is a expression that is equivalent to 2x^2 + (4x-5x^2) +9-(6x+3)

Katlyn made 4 dresses with 7 yards of fabric. how many yards did she use on 1 dress?

Ihave a 69 and an 82. the 69 is worth 40% of my grade and the 82 is worth 15%. can someone tell me my current average grade.

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia