Please help question in picture

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

What is the relationship between all triangles that can be drawn given the same three angles

Television sizes are based on the length of the diagonal of the television's rectangular screen. so, for example, a 70-inch television is a television having a diagonal screen length of 70 inches. if a 70 inch television's diagonal forms a 29°angle with the base of the screen, what is the vertical height (1) of the screen to the nearest inch? 70 inhin