Question 805274
x is short leg
y is long leg
hypotenuse is x+8, directly from the description as worded with use of x.
y = 16, as from the description and assignment of y, long leg.


{{{x^2+y^2=(x+8)^2}}}, Pythagorean Theorem.
{{{x^2+16^2=(x+8)^2}}}
{{{x^2+16^2=x^2+16x+64}}}
See the term, {{{x^2}}} on both sides, shown as "positive" term.
{{{16^2=16x+64}}}
{{{16x+64=16^2}}}
{{{16x=16^2-64}}}
{{{x=(16^2-64)/16}}} very convenient values.
{{{x=(16^2)/16-64/16}}}
{{{x=16-2*4*2*4/(4*4)}}}
{{{x=16-4}}}
{{{highlight(x=12)}}}, which is the length of the short leg.  The {{{highlight(hypotenuse)}}} was described in terms of this x value.



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Hypotenuse is {{{h=x+8=12+8=highlight(20)}}}