Algebra 2 - Grade 11 Can anyone please help me with these Algebra 2 Math questions?

Soon as possible !!!

Find p(–4) if p(x) = 3x^3 – 2x^2 + 6x – 4

If r(x) = x^3 – 2x + 1, find r(2a^3).

Find p(–4) if p(x) = 3x^3 – 2x^2 + 6x – 4

p(-4) = 3x^3 – 2x^2 + 6x – 4

p(-4) = 3(-4)^3 – 2(-4)^2 + 6(-4) – 4
= 3(-64) - 2(16) + 6(-4) - 4
= -192 - 32 - 24 - 4
p(-4) = -252

r(x) = x^3 – 2x + 1, find r(2a^3)

r(x) = (x^3 – 2x + 1) (2a^3)
= (2a^3) x^3 + (2a^3) (-2x) + (2a^3) * 1
= x^3 (2a^3) - 2x (2a^3) + 1 * (2a^3)
r(x) = 2a^3x^3 - 4a^3x + 2a^3

I’m not entirely sure about this one as I’m also in 11th grade but I think this is how it’s done.