10+3b-(8b+2)-5+b=10+3b-8b-2-5+b=3-4b
b=-10 3-4(-10)= 3+40=43
Ответ: 43.
1) a25=a1 + (25-1) * -2
a25=18 + 24*-2
a25= 18-48=-30
S= (a1+ a25) *n/2= (18-30) * 25/2= -12 *25/2=-6*25=-150
2) b5=b1* q^4
b5= 6 *3^4=6* 9*9=6*81=486
s= (b1*b5-q)/ q-1
s= 6* 486-3/2=6*243=1458
<span>1)
2x</span>²<span>+ 24xy +72y</span>² = 2 ·(х²+12ху+36у²) = 2·(х+6у)² = 2·(х+6у)(х+6у)
<span>2)
-8a</span>⁵<span> +8а</span>³<span> - 2а = -2а</span>·(4а⁴-4a²+1) = -2a·(2a²-1)² = -2a·(2a²-1)(2a²-1)
<span>3)
5a</span>³<span> - 40b</span>⁶ = 5a³ ·(1-8b³) = 5a³ ·(1³ - (2b)³) = 5a³·(1-2b)(1+2b+4b²)
<span>4)
8а</span>³<span> -аb - a</span>²<span>b + а</span>² = a·(8a²-b-ab+a)
Z²=a²-b²+2abi=9+4-12i=13-12i
w=13-12i+3i-1=12-9i
12×(-9)=-108