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Find the vertex of the graph f(x)=2x^2 - 5x +8

User Mjaniec
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1 Answer

1 vote

Answer:

(1.25, 4.875)

Explanation:

To find the vertex we need to complete the square. In order to do this we need the coefficient of x² to be 1, so we take out a factor of 2 from the x² and x terms to get f(x) = 2(x² - 5/2x) + 8.

Now we complete the square as follows:

f(x) = 2[(x - 5/4)² - 25/16] + 8

f(x) = 2(x - 5/4)² - 25/8 + 8

f(x) = 2(x - 5/4)² + 39/8

Hence the vertex has coordinates (1.25, 4.875).

User Scorer
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