How do I solve 6=1/2z

Bradley hikes 12 miles in 3 hours. in relation to bradley’s hike, which statement describes the expression

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

Asystem of equations has 1 solution. if 4x-y=5 is one of the equations , which could be the other equation ?