5ab/(a+5b)*(a²-25b²)/ab=5*(a-5b)(a+5b)/(a+5b)=5(a-5b)
a=5√7+9,b=√7-9
5*(5√7+9-5√7+45)=5*54=270
5×16×90,64×0,36×9=23493,888
P^2 + 12pk + 36k^2 = (p + 6k)^2
q=a2/a1=a3/a2=a4/a3=-----------
a1=12,a2=4,a3=4/3,............
q=4/12=1/3
q=1/3
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16x^2-8x+1-(12x^2-8x-15) > 4x^2-16x+16 +16
4x^2+16>16x+32
16>-16+32
16x>16
x>1