1
a)12m^4/k³*k^6/9m²=4m²k³/3
б)3x²/(4-y)(4+y) * (4+y)/15x^5=1/5x²(4-y)
в)(x-1)(x+1)/(x-2)(x+2) *5(x+2)/(x+1)=5(x-1)/(x-2)
2
1)2x/(x-2)-1/(x+2)=(2x²+4x-x+2)/(x²-4)=(2x²+3x+2)/(x²-4)
2)(2x²+3x+2)/(x²-4) * (x²-4)/3(2x²+3x+2)=1/3
3
1)(m-k)(m+k)/m(m+k) * k²/(m-k)²=k²/m(m-k)
2)k/(k-m)-k²/m(k-m)=(km-k²)/m(k-m)=k(m-k)/m(k-m)=-k/m
4
(x+1)/(x-3)-7/x=1
ОЗx(x-3)≠0⇒x≠0;x≠3
x(x+1)-7(x-3)=x(x-3)
x²+x-7x+21-x²+3x=0
3x=21
x=7