Math Help please

Question

Find p(x) = 3x^2-4 and r(x)= 2x^2 -5 +1, find each value. 

1. p(8a)

2. -5r(2a)

3. p(x^2-1)

Answer 1

p(x) = 3x² - 4

r(x) = 2x² - 5 + 1

 

When your write p(8a) it means p(x=8a), so just replace the x in p(x) with 8a.

 

p(x) = 3x² - 4

p(8a) = 3(8a)² - 4 = 3(64a²) - 4 = 192a² - 4

 

For -5r(2a), replace x in r(x) with 2a, then multiply the whole thing by -5.

 

For p(x²-1), replace the x in p(x) with x²-1:

 

p(x) = 3x² - 4

p(x²-1) = 3(x²-1)² - 4

 

Can you finish it?