Can anyone tell/explain the answer

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)

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

What multiplys to be 1 but adds up to be 4