Please help. This question is on geometric sequences

What is the first step of an indirect proof of a number that is divisible by two

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

3x + 4y = 5 x- 3y = -7 solve by substitution