The ratio of the height (h) of the streetlight to its distance to the end of Laura's shadow is the same as the ratio of Laura's height to her distance from the end of her shadow.
.. h/(12+9) = 5'4"/9
.. h = (21/9)*5'4" = 12 4/9 feet
.. h = 12 ft 5 1/3 inches
The streetlight is 12 ft 5 1/3 inches tall.
Add these together.
You get -15y=-45
So y=3
Now plug in to first equation.
8x-8(3)=-16
8x-24=-16
8x=8 so x=1
Check both values in second equation.
-8(1)-7(3)=
-8-21=-29
It works...so x=1, y=3
Since the coefficients of d are not equal, then there can only be one solution
This is the isosceles right triangle, the diagonal of a square, the thing that so upset the Pythagoreans. The two sides and diagonal of a square are in ratio 
so we get
We could have also gotten this using Trig:
Or by recognizing u=v because remaining angle is 45 so this must be isosceles so
The answer would be stem and leaf plot
