Please help!! I am struggling on cross-sections

After applying the composition r0.90 ry to rs what are the coordinates of r' and s'? a.r'(–3, 1),  s'(–3, 5)b.r'(–1, 3),  s'(–5, 3)c.r'(1, 3),  s'(5, 3)d.r'(5, 3),  s'(1, 3)

What is best way to getting answer for my exam is

What is the value of the expression i 0 × i 1 × i 2 × i 3 × i 4? 1 –1 i –i