SOLUTION: If f(x)= x²+2x, then find f(a+h)-f(a)

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Question 618359: If f(x)= x²+2x, then find f(a+h)-f(a)
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
If f(x)= x²+2x, then find f(a+h)-f(a)
.
find f(a+h):
f%28a%2Bh%29+=+%28a%2Bh%29%5E2+%2B+2%28a%2Bh%29
f%28a%2Bh%29+=+%28a%2Bh%29%28a%2Bh%29+%2B+%282a%2B2h%29
f%28a%2Bh%29+=+a%5E2%2B2ah%2Bh%5E2+%2B+2a%2B2h
.
find f(a):
f%28a%29+=+a%5E2+%2B+2a
.
then f(a+h)-f(a):
%28a%5E2%2B2ah%2Bh%5E2+%2B+2a%2B2h%29+-+%28a%5E2+%2B+2a%29
a%5E2%2B2ah%2Bh%5E2+%2B+2a%2B2h+-+a%5E2+-+2a
2ah%2Bh%5E2+%2B+2a%2B2h+-+2a
2ah%2Bh%5E2%2B2h
ordering terms:
h%5E2%2B2ah%2B2h