Y=−8x−3 x+y=7 Is (3,4) a solution of the system?

Express in the simplest form: (x^2+9x+14/x^2-49) / (3x+6/x^2+x-56)

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

If the perimeter of the garden is 37 ft. the width is x and the length is 15 ft. what is the width of the garden in feet?