Hi I have problems in some questions.

A) My answers to these questions do not match the book answers:-

1) The three vertices of a paralleologram are $\displaystyle (3,4), (3,8)$ and $\displaystyle (9,8)$. Find the fourth vertex.[Book Answer:$\displaystyle (9,4)$](Solved)

2) The area of a triangle is $\displaystyle 5$. Two of its vertices are $\displaystyle (2,1)$ and $\displaystyle (3,-2)$. The third vertex lies on $\displaystyle y=x+3$. Find the third vertex.[Book Answer:$\displaystyle (7/2,13/2)$ and $\displaystyle (-3/2,3/2)$. How am I supposed to get the second answer](Solved)

3) The point $\displaystyle A$ divides the join of $\displaystyle P(-5,1)$ and $\displaystyle Q(3,5)$ in the ratio $\displaystyle k:1$. Find the values of $\displaystyle k$ for which the area of triangle ABC where $\displaystyle B$ is $\displaystyle (1,5)$ and $\displaystyle C(7,-2)$ is equal to 2 units.[Book Answer:$\displaystyle k=7$ or $\displaystyle 31/9$]

B) Can't even guess what to do:-

1) Find the locus of the mid-point of the portion of the line $\displaystyle x$ $\displaystyle cos\alpha$ $\displaystyle +$ $\displaystyle y$ $\displaystyle sin\alpha$ $\displaystyle =$ $\displaystyle p$ which is intercepted between the axes.[Book Answer:$\displaystyle p^2(x^2+y^2)=4x^2y^2$]

2) Find the equation of the bisector of angle $\displaystyle A$ of the triangle whose vertices are $\displaystyle A(4,3), B(0,0)$ and $\displaystyle C(2,3)$.[Book Answer:$\displaystyle x-3y+5=0$](Solved)

3) Find the distance of the point $\displaystyle (3,5)$ from the line $\displaystyle 2x+3y=14$ measured parallel to a line having slope $\displaystyle 1/2$.[Book Answer:5^(1/2)](Solved)

4) Find the distance of the point $\displaystyle (2,5)$ from the line $\displaystyle 3x+y+4=0$ measured parallel to a line having slope $\displaystyle 3/4$.[Book Answer:$\displaystyle 5$ $\displaystyle units$](Solved)

That's all. Thanks