1) −0,8z5(1,2m5−2,5z) = -0.96z5m5+2z6
2) 11p3d(d3p−d3)=11p4d4−11p3d4
3) x9y2z(x2+10y2+7z2)=)x11y2z+10x9y4z+7x9y2z3
4) (4a3−3b)⋅2b−3b⋅(14a3−4b)=8a³b-6b²-42a³b+12b²= -34a³b+6b²
5) −9t2(2t5−3k)+5(4t7−2k)=-18t7+27t²k+20t7-10k=2t7+27t²k-10k
6) 13ab(14a²−b2)+14ab(b²−13a²)=182a³b-13ab³+14ab³=182a³b=ab³
10*(-2)³=10*(-8)=-80
7) 0,8(4a+3b)−6(0,3a+0,8b)=3.2a+2.4b-1.8a-4.8b=1.4а-2.4b
1.4*2-2.4*(-4)=2.8+9.6=12.4
8) 3x−ay+bz=3*(5с3+2)-3с(6с2-с+14)+15с3*(5с-1)=15с3+6-18с3+3с2-42с+75с4-15с3=75с4+(-18с3)+3с2+(-42с)+6
Объяснение:
Вот накалякал. Разбирайся :)
xy/(x+y) = 5
xz/(x+z) = 7
yz/(y+z) = 9
xy = 5x + 5y
xz = 7x + 7z
yz = 9y + 9z
x(y-5) = 5y
x = 5y/(y-5)
5yz/(y-5) = 35y/(y-5) + 7z
5yz = 35y + 7z * (y-5)
5yz = 35y + 7yz - 35z
2yz + 35y = 35z
y(2z + 35) = 35z
y = 35z/(2z + 35) = z/(2z/35 + 1)
35z^2/(2z + 35) = 315z/(2z + 35) + 9z
35z^2 = 315z + 9z*(2z + 35)
35z^2 = 315z + 18z^2 + 315z
17z^2 = 630z
z=630/17
y = 35*630/(2*630/17 + 35)/17 = 35*630/(1260 + 595) = 22050/1855 = 630 / 53
x = 5*630/(630/53 - 5)/53 = 5*630/((630/53 - 5)*53) = 5*630/365 = 630/73
