<span>9x^2-10a^3+6ax-15a^2x = (</span><span>9x^2+6ax) - (15a^2x</span><span>+10a^3) = 3х(3х+2а) - 5</span><span>a^2(</span>3х+2а) = (3х+2а)*(3х-5a^2)
(2a-b)^3-(2a+b)^3 = 8a^3-12a^2b+6ab^2-<span>b^3 - </span> 8a^3-12a^2b-6ab^2-b^3 = -24a^2b - 2b^3 = -2b*(12a^2+<span>b^</span>2)
Ответ:
Объяснение:
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а5=9 а1+4d=9 a1=9-4d a2+a9=20 a1+d+a1+8d=20 2a1+9d+20
2(9-4d)+9d=20 18-8d +9d=20 d=20-18 =2
Sn=(2a1+(n-1)d/2)*n S10=(2+18/2)*10 = 100
11
1)y/(y-6)-2y/(y-6)=(y²-6y-2y)/(6-y)²=y(y-8)/(6-y)²
2)(6-y)(6+y)/(y-8) *y(y-8)/(6-y)²=y(6+y)/(6-y)
3)(6y+y²)/(6-y)-12y/(6-y)=(6y+y²-12y)/(6-y)=y(y-6)/(6-y)=-y
12
х-время автобуса,х-1,5-время автомобиля
80(х-1ю5)=60х
80х-120=60х
80х-60х=120
20х=120
х=6
6*60=360км расстояние
13
AM_|_BC,CN_|_AB,BC∧CN=O
<BNO=<BOM=90,<B=70⇒<MON=360-2*90-70=110
Решение
81у^2-36xy-60x^2 = (81y² - 36xy + 4x²) - 4x² - 60x² =
= (9y - 2x)² - 64x² = (9y - 2x - 8x)*(9y - 2x + 8x) =
= (9y - 10x)*(9y + 6x) = 3*(<span>9y - 10x)*(3y + 2x)</span>