What is the answer to y=6+4x and y=-5x-21

Bring the fraction a/a-4 to a denominator of 16-a^2

Of the 304 people who attended a school play, 5/8 were students. how many of the people who attended were students.

What are the solutions for the following system? -2x^2+y=-5 y=-3x^2+5