Find the circumcenter of triangle ABC

Hardest math question of all time can you solve the equation. check for extraneous solutions.9∣9-8x∣ = 2x+3

For f(x) = 3x+1 and g(x) = x2 - 6, find (g/f)(x)

Milk and ice cream are mixed together for a recipe. the total volume of the mixture is 1 cup. if the milk contains 2% fat, the cream contains 18% fat ,and the mixture contains 6% fat ,how much cream is in the mixture