C3=32 q=1/2 S5-?
S5=c1(1/2^5-1)
1/2-1
c3=c1*q^2
32=c1*1\2^2
32=c1*1\4
c1=128
S5=128(1\32-1)
-1\2
S5=128*(-31\32)
-1\2
S5=-124:(-1\2)
S5=248
2XY + X^2 - ( X + Y)^2 = 2XY + X^2 - ( X^2 + 2XY + Y^2 ) =
= 2XY + X^2 - X^2 - 2XY - Y^2 = - Y^2
Ответ ( - Y^2 )
8х+15*0=32
15*0=0
32-0=32
32:8=4
8*4+15*0=32
5x-3y=8 -1=7 y+2x=5 (5-2x=3y)