Answer:
-56 + 3 sqrt(2) /2
Step-by-step explanation:
f(x) = x^2 +2/sqrt{x}.
2f(2) - f(8).
First find f(2)
f(2) = 2^2 +2/sqrt{2} = 4 + 2/ sqrt(2)
Then f(8)
f(8) = 8^2 +2/sqrt{8} = 64 + 2 / sqrt(4)sqrt(2) = 64+ 2/2sqrt(2) = 64 + 1/ sqrt(2)
2f(2) - f(8).
2 * (4 + 2/ sqrt(2)) - (64 + 1/ sqrt(2))
8 + 4/ sqrt(2) - 64 - 1/ sqrt(2)
Combine like terms
-56 + 3 / sqrt(2)
Rationalizing the second term
-56 + 3/ sqrt(2) * sqrt(2)/sqrt(2)
-56 + 3 sqrt(2) /2
