6(9+4х)=4х-4; 54+24х=4х-4; 24х-4х=-4-54;
20х=-58; х=-58:20; х=-2,9
4.(степени буду писать сзади обычными цифрами)
а)15•а2•b+10•a3•b2•c
б)3m+3n-m2-2nm-n2
Пусть а¹/²=t ⇒
((t+2)/(t²+2t+1)-(t-2)/(t²-1))*(t+1)/t=((t+2)/(t+1)²-(t-2)/((t+1)(t-1)))*(t+1)/t=
=((t+2)(t-1)-(t-2)(t+1))/((t+1)²(t-1))*(t+1)/t=(t²+t-2-t²+t+2)/((t+1)²(t-1))*(t+1)/t=
=(2t/(t+1)²(t-1))*(t+1)/t=2t*(t+1)/((t*(t+1)²(t-1))=2/((t+1)(t-1))=2/(t²-1)=
=2/((a¹/²)²-1)=2/(a-1).
<span>53
(a+b)³ - a²(a+b)²/a +b²(a-b)²/b=(a+b)³-a(a²+2ab+b²)+b(a²-2ab+b²)=
=a³+3a²b+3ab²+b³-a³-2a²b-ab²+a²b-2ab²+b³=2a²b+2b³=2b(a²+b²)
2b(a²+b²)≠4ab²
54
(y³+12y²+48y+64-9y²-48y-64)/y²=-1
(y³+3y²)/y²=-1
y²(y+3)/y²=-1
y+3=-1
y=-1-3
y=-4</span>