cред аримфметич
1.4 + 1.8 + 1.1 + 2 + 4.7 + 1 + 2 + 2 = 16
16/8=2
Медиана
1.4 + 1.8 + 1.1 + 2 + 4.7 + 1 + 2 + 2 = 16
16/2 + 16/2 = 16
16=16
<span>(1-х)(х+1)+(х-1)</span>
а) = sin (81градус - 21градус)=sin 60градусов = (корень из 3)/2
б) = cos (5П/8 + П/8) = cos 6П/8 = cos 3П/4 = - (корень из 2)/2
1)(a+3b)²/[4(a-3b)]-4a=(a²+6ab+9b²-16a²+48ab)/[4(a-3b)=
=(-15a²+54ab+9b²)/[4(a-3b)]=-3(5a²-18ab-3b²)/[4(a-3b)]
2)-3(5a²-18ab-3b²)/[4(a-3b)]* 8(3a-2)/[3(a+3b)] * (a-3b)(a+3b)/(5a²-18ab-3b²)=
=-2(3a-2)=4-6a
a=-2/3,b=7/3 4-6*(-2/3)=4+4=8