3a+b=54 when b=9 what is the value of a

For which rational expression is -2 an excluded value of x?

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

Solve 3x-18=2y and 5x-6y=6 by elimination show work