SOLUTION: evaluate f(a+1) if f(x)=x^2+2x+5

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Question 666524: evaluate f(a+1) if f(x)=x^2+2x+5
Answer by Leaf W.(135) About Me  (Show Source):
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f(x) = x%5E2+%2B+2x+%2B+5; evaluate f(a + 1)
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In f(a + 1), the a + 1 is taking the place of the x in f(x). As a result, simply plug the the a + 1 into the equation for f(x), exchanging each instance of x with a + 1: f(a + 1) = %28a+%2B+1%29%5E2+%2B+2%28a+%2B+1%29+%2B+5
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Use the FOIL method to simplify %28a+%2B+1%29%5E2: f(a + 1) = a%5E2+%2B+2a+%2B+1+%2B+2%28a+%2B+1%29+%2B+5
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Distribute the 2 into the a + 1: f(a + 1) = a%5E2+%2B+2a+%2B+1+%2B+2a+%2B+2+%2B+5
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Simplify by adding together the 2a and 2a and the 1, 2, and 5: f(a + 1) = a%5E2+%2B+4a+%2B+8
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Your final answer is f(a + 1) = a%5E2+%2B+4a+%2B+8