Answer: 2p^2 + 18p + 61
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Explanation:
Everywhere you see an x, replace it with p+4, then simplify.
We'll use the FOIL rule to expand out (p+4)^2
So...
g(x) = 2x^2 + 2x + 21
g(x) = 2( x )^2 + 2( x ) + 21
g(p+4) = 2( p+4 )^2 + 2( p+4 ) + 21 .... every x replaced with p+4
g(p+4) = 2(p^2+8p+16) + 2(p+4)+21 .... FOIL rule
g(p+4) = 2p^2+16p+32 + 2p+8+21 .... distribute
g(p+4) = 2p^2 + 18p + 61
