some math help?

Question

1.
http://i6.photobucket.com/albums/y250/starbase176/hw2.jpg

2. Simplify
5/x + 4/x^2 - 3/x^3

3. Solve for a
4a + 7 - 3b=23

4. Simplify
p^-4x^2/x^-7 - 4x^9/p^4 + 6x^14/p^4x^5

5. Find the least common multiple of
4a^2c and 14abc^5

Answer 1

1. y^2/(5x^3 z^3) + 10z/x

2. (5x^2+4x-3)/x^3

3. a=(16+3b)/4

4. 3x^9/p^4

5. 28 a^2 b c^5

Answer 2

=1/x^2z^3[y^2/5x + 10xz^4/3]
=1/x^2z^3[3y^2/15x + 50x^2z^4/15x]
= [3y^2 +50x^z^4]/[x^2z^3*15x]
=[3y^2 +50x^z^4]/[15x^3z^3]

= 5x^2/x^3 +4x/x^3 - 3/x^3
= (5x^2+4x-3)/x^3

4a = 23 +3b -7
4a = 16+3b
a = 4 + 3b/4

= x^9/p^4 - 4x^9/p^4 + 6x^9/p^4
= 3x^9/p^4

=2ac