Can anybody please help me show my work for these problems....I have the correct answer just no work to prove it... 
 1.Given f(x) = x2 + 2x, find f(a _ 3)
 A: a^2-4a+3
 2. If f(x0=x/x-3 and g(x)=2x-1, find (f-g)(x)
 A: -2x^2+8x-3/x-3
 3. If f(x)=x^2+1 and g(x)=1/x, find [f*g](x)
 A:1/x^2 +1
 4. Which equation best represents a line perpendicular to the graph of x+3y=9?
 A:y=3x-1
 5. Which of the following describes the graphs of 2x+5y=9 and 10x=4y+18?
 A: perpendicular
 6. Write the standard form of an equation of the line parallel to the graph of x-2y-6=0 and passing through A(