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If f(x) = x^2 + 9x, find f(a - 4)

1 Answer

7 votes
To solve this, you plug a-4 in wherever you see an x
f(a-4)=(a-4)(a-4)+9(a-4)
Then you distribute to simplify
=a^2-4a-4a+16+9a-36
=a^2+a-20

Hope this helps
User Kaaf
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