HELP PLS ILL GET FINES AND HELD BACK AND IM POR

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)

Plzz ! if you were constructing a triangular frame, and you had wood in the length of 4 inches, 4 inches, and 7 inches, would it make a triangle? would you be able to create a frame from these pieces of wood? yes or no? = explain your mathematical thinking/show your work:

Acone with radius 5 cm and height 12 cm how many cm ?