First year: the depreciation is (35/100) x 20000 = £7000; now the value of the car is £20000 - £7000 = £13000;
Second year: the depreciation is (35/100) x 13000 = £4550; the current value of the car is £13000 - £4550 = £8450.
Domain: x≤5 (notice the closed dot on the right and the arrow on the left)
Range: y≤2 (notice the closed dot on the right and the arrow on the left)
The arrow means it keeps going infinitely. The closed dot means it stops there but is inclusive of that value.
Choice C, because

So it's less than what she originally had (which isn't possible)
Vertical angles, because the definition of vertical lines is each of the pairs of opposite angles made by two intersecting lines.