What makes a unique triangle a unique triangle?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

The midpoints of the sides of the large square are joined to form a smaller square. what is the area of the smaller square

You’re giving a cube with a length of 2.5 cm and a width of 2.5 cm and a high of 2.5 cm you place it on a scale and it is 295 g calculate the density