A plane traveled 880 miles each way to Bangkok and back. The trip there was with the wind. It took 10 hours. The trip back was into the wind. The trip back took 20 hours. Find the speed of the plane in still air, in miles per hour.

Step-by-step explanation:

Let x miles/hr be the speed of the plane in still air and y miles/hr be the speed of the wind.

We have 10hr * (x + y)miles/hr = 880 miles

and 20 hr * (x - y)miles/hr = 880 miles.

=> (x + y) = 88 and (x - y) = 44.

Therefore 2x = 88 + 44 = 132 and x = 66.

The speed of the plane in still air is 66 miles per hour.

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graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.