Practicing Success
If $a^2 + b^2 + c^2 + 48 = 8(a + b + c)$, then what is the value of \(\sqrt[3]{a^3-b^3+c^3}\) ? |
6 4 3 2 |
4 |
a2 + b2 + c2 + 48 = 8(a + b + c) = a2 - 8a + 16 + b2 - 8b + 16 + c2 - 8c + 16 = 0 = (a - 4)2 + (b - 4)2 + (c - 4)2 = 0 When the sum of the squares is 0 then the value of each of them is equal to 0. So, a - 4 = 0 b - 4 = 0 c - 4 = 0 = a = b = c = 4e Now the value of \(\sqrt[3]{a^3-b^3+c^3}\) = \(\sqrt[3]{4^3-4^3+4^3}\) = \(\sqrt[3]{64}\) = 4 |