a few questions I need help with. thank you

Okay I am almost done with this lesson. Once again I need help. UGH.. I already did this but received an F and I am fixing all the wrong answers.

Please show me how you got the answers. I would still like to learn instead of just knowing the answer. Plus I need to know what I did wrong.

1. What is the equation of a horizontal line that passes through the point at (-2,-3)?

2. In a circle whose diameter is 20inches, a chord is 6inches from the center. What is the length of the chord?

3. Use the Law of Syllogism to determine a conclusion.

(1) All squares are rhomubuses

(2) The diagonals of a rhombus are perpendicular.

4. What are the coordinates of the image of the point at (-3, -5) after a reflection over the y-axis?

5.Find the measure of an angle if its measure is 4 times the measure of its comlement.

6. Write an equation of the line that passes through the point at (4,4) and is perpendicular to the line whose equation is 2x+y=7.

7. Classify triangle ABC by its angles if m<B=26 and m<A=64.

8. Find the length to the nearest tenth, of the apothem of a regular octagon whose sides are 10inches long.

9. Solve the system of equation:

3x+2y=17

2x-y=9

Please help.. I already did this. I have to redo to get a better grade. I already fixed most of them on my own.