ii)
L3 equation is x = 2 as it is a vertical line that intersects 2 on the x axis.

iii) by using the perpendicular formula you can prove that L1 is not perpendicular to L2 since the gradient of L2 should be the same as -1 / L1 gradient

iv) question says L4 is parallel to L1. Therefore, the gradient is -5.
To find the constant, you will need to sub in coordinates. But because the y coordinate is hard to find, we will instead find the constant in terms of x first then sub in the x coordinate of C.

v) find C and D by subbing in x, y respectively then just use the area formula you have learnt in school

In order to find theta, you need to trigo. But since they have not given you the length of the triangle, you will need to find the length first.