1) (a+3)^2 + (a-3)(a+3) + 6a = a^2 + 6a + 9 + a^2 - 3^2 +6a = 2a^2 + 12a
2) xy-2y=y(x-2)
16a^2 - 81 = 4^2a^2 - 9^2 = (4a-9)(4a+9)
3x^2 - 6x^3 = 3x^2(1-2x)
x^2-10x+25 = (x-5)^2
3(x-1) +y(x-1) = (x-1)(3+y)
2a^2 - 4ab + 2b^2 = 2(a-b)^2
3) a^2 - 3ab + 3a - 9b = a(a+3) - 3b(a+3) = (a+3)(a-3b) = (1 + 3)*[1-3*(-1/3)]=
= 4*[1 + 1] =8
<span>(735+728)2-4*735*728=(1463)2-4*1463=2140369-5852=2134517</span>
X1=(6-b)/5 x2=(12-b)/6
1)x2>x1
(12-b)/6>(6-b)/5
5(12-b)-6(6-b)>0
60-5b-36+6b>0
b>-24
возрастающая при b∈(-24;∞)
2)x2<x1
убывающая при b∈(-∞;-24)
Sn<span><span> = <span>b1(qn - 1)/</span></span><span>q - 1
S7=-256(-0.5^7-1)/-0.5-1=-172
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