X<<span>y+<span>3 its simple here is your answer</span></span>
Let y be the unknown number
The other number is x - 12
To find range, you must find the largest number in your data, and subtract it by the smallest number in your data.
In this case...
the Largest (20) - smallest (0) = Range
X and w is 105 degrees and y and z are 86 degrees. since line L is a straight line it would have to add up to 180 and same with line M