( 4 - 4n + n^2)÷( n^2 - 4/2) = (n^2 - 4n + 4)÷(n - 2)(n + 2) / 2 =
= (n - 2)(n - 2)× 2 / (n - 2)(n + 2)= 2(n - 2) / ( n + 2)
Блин не помню...........
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<span>4a+9b=40
a= (40 - 9b)/ 4</span>
115.
1) (3c+1 +c(c-1)) /(c-1) = (3c+1+c^2-c) /(c-1) =
=(c^2+2c+1) /(c-1) =(c+1)^2 /(c-1)
2) (c+1)^2 /(c-1) × 1/(c+1) =
=(c+1)^2 /(c-1)*(c+1) =(c+1) /(c-1)