Solve for x x-xy=z Hint: reverse distribution to get x alone

Work Shown:

x - xy = z

x*1 - x*y = z

x*(1 - y) = z distributive rule in reverse

x = z/(1-y) divide both sides by (1-y)

The distributive rule is a*(b+c) = a*b+a*c. You can also say a*(b-c) = a*b-a*c. In this case, we factored out the common factor x.

ok then what happened.

geometry: triangles

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call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

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