Решите уравнение 1/2x2 - 1/2= 1/6x( x+ 5)

1/2x^2-1/6x^2-5/6x-1/2=0

1/3x^2-5/6x-1/2=0|*6

2x^2-5x-3=0

d=25-4*2*(-3)=25+24=49

x=(5+7)/4     x=3

или             или

x=(5-7)/4     x=-1/2

s={-1/2; 3}

1)2х²-8=2(х²-4)=2(х-2)(х+2) 2)18-2y²=2(9-у²)=2(3-у)(3+у) 3)kt²-k=k(t²-1)=k(t-1)(t+1) 4)32a³-2a=2a(16a²-1)=2a(4a-1)(4a+1) 5)2u³-2v³=2(u³-v³)=2(u-v)(u²+u*v+v²) 6)nx³+nz³=n(x³+z³)=n(x+z)(x²-x*z+z²) 7)w⁴-w=w(w³-1)=w(w-1)(w²+w+1) 8)z⁴+8z=z(z³+8)=z(z+2)(z²-2*z+4) 9)x⁴-16z⁴=(x²-4z²)(x²+4z²)=(x-2z)(x+2z)(x²+4z²) 10)81-k⁴=(9-k²)(9+k²)=(3-k)(3+k)(9+k²) 11)2a²-12a+18=2(a²-6a+9)=2(a-3)² 12)10x-5x²+5=5(2x-x²+1)=-5(x²-2x-1) 13)0,5u²+4uv+8v²=0.5(u²+8uv+16v²)=0.5(u+4v)² 14)-0,9x²-0,6xy-0,1y²=-0.1(y²+6xy+9x²)=-0.1(y+3x)² 15)t³-8t²+16t=t(t²-8t+16)=t(t-4)² 16)4u³+4u²+u=u(4u²+4u+1)=u(2u+1)² 17)x³-4x²y+4xy²=x(x²-4xy+4y²)=x(x-2y)² 18)pt²+6p²t+9p³=p(t²+6pt+9p²)=p(t+3p)² 19)4a²(тут наверное куб)+12a²b+9ab²=a(4a²+12ab+9b²)=a(2a+3b)² 20)9x³y-12x²y²+4xy³=xy(9x²-12xy+4y²)=xy(3x-2y)² 21)x²(x-1)+4x(x-1)+4(x-1)=(x-1)(x²+4x+4)=(x-1)(x+2)² 22)36(y+2)+12y(y+2)=(y+2)(36+12y)=12(y+2)(3+y) 23)25x²(x²-1)-10x(x²-1)+x²-1=(x²-1)(25x²-10x+1)=(x-1)(x+1)(5x-1²) 24)9a²(a²-b²)+12ab(a²-b²)+4b²(a²-b²)=(a²-b²)(9a²+12ab+4b²)=(a-b)(a+b)(3a+2b)² 25)4a-4-a³+a²=4(a-1)-a²(a-1)=(a-1)(4-a²)=(a-1)(2-a)(2+a) 26)3b³+3b²-3b-3=3b²(b+1)-3(b+1)=(b+1)(3b²-3)=3(b+1)(b²-1)=3(b+1)(b-1)*(b+1)=3(b+1)²(b-1) 27)5c³+10c²-5cd²-10d²=5c²(c+2)-5d²(c+2)=5(c+2)(c-d)(c+d) 28)3k³+3k²-3km²-3m²=3k²(k+1)-3m²(k+1)=3(k+1)(k-m)(k+m) 29)8x-8-x⁴+x³=8(x-1)-x³(x-1)=(x-1)(2-x)(4+2x+x²) 30)y⁴+2y³+27y+54=y³(y+2)+27(y+2)=(y+2)(y+3)(y²-3y+9) 31)x²-4x+4-y²=(x-2)²-y²=(x-2-y)(x-2+y) 32)y²+10y+25-x²=(y+5)²-x²=(y+5-x)(y+5+x) 33)4z²+4uz+u²-16=(2z+u)²-16=(2z+u-16)(2z+u+16) 34)81-9x²-6xy-y²=9(9-x² )-y(6x+y)=9(3-x)(3+x)-y(6x+y)

70> r< 80 вот и всё! пока удачи.