6x-3x=c-4a;
3x=c-4a;
x=(1/3)*c-(4/3)*a
27=1/2*3x/2
27=3x/4
3x=27*4
3x=108
x=36
A)cos^2a+sin^2a=1
1+tg^2a=1+tg^2a
b)-cos^2a+1=sin^2a
2sin^2a=2sin^2a
c)sin^2a-1=-cos^2a
-cos^2a= -cos^2a
(с³-3с²)/(9-с²)=с²(с-3)/-(с-3)(с+3)= - с²/(с+3)
(5а³в+5ав³)/а⁴-в⁴= 5ав(а²+в²)/(а²+в²)(а²-в²)=5ав/(а²-в²)
(х³+у³)/3(х+у)²=(х+у)(х²-ху+у²)/3(х+у)(х+у)=(х²-ху+у²)/(х+у)
(50х²-32у²)/(5х-4у)²=2(5х-4у)(5х+4у)/(5х-4у)(5х-4у)=2(5х-4у)/(5х+4у)