how do I figure this out 2x(squared)-4x-1=0?

The perimeter of the rectangle is 14 feet, and the area is 12 square feet. What is the width of the rectangle? I only have one example to go by and I don't get how it works with this problem.

1.paul rode his motorbike for X hours at an average speed of (30x + 5)km/h. if the total distance travelled was 385km find his average speed for the jorny? solve this question by using quadratic equations formula.:)

A rain gutter is to be made up of rectangular aluminum sheets 12 inches wide by turning up the sides edges 90 degrees. What depth (of the edges) will provide a maximum cross sectional area and thereby provide for the greatest flow of water? (Hint, think of quadratic equations and you want to...

A rectangular animal pen with the area 1200m has one sidealong a barn. The other three sides are enclosed by a 100m fencing. Find the dimensions of the pen.