1)n(n-5)/(n-5)²+25/(n²-25)=n/(n-5)+25/[(n-5)(n+5)]=
=(n²+5n+25)/[(n-5)(n+5)]
2)(n²+5n+25)/[(n-5)(n+5)] *(5+n)/[(5-n)(25+5n+n²)]=
=-1/(5-n)*1/(5-n)=-1/(5-n)²
327³ + 173³ =(327+173)(327² - 327*173+173²) =500*(327² - 327*173+173²) .
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(2n+3)² -(2n-1)² =(2n+3-2n+1)(2n+3+2n-1)=4(4n+2) =8*(2n+1).
X+y=-4
x²+y²-2xy=36
(x-y)²=36 x-y=6 x-y=-6
x+y=-4
x-y=6
2x=2
x₁=1 y₁=-5.
x+y=-4
x-y=-6
2x=-10
x₂=-5 y₂=1.
Ответ: x₁=1 y₁=-5 x₂=-5 y₂=1.
302*324+121=2*151*2*2*3*3*3*3+11*11
25x^3+3*5x*4y^2+3*25x^2+4y^3