Ответ:
Объяснение:
x+(7x2 -21x)*(3x+2)≤0
x+21x³ +14x² -63x² -42x≤0
-41x+21x³ +14x² -63x² ≤0
-41x+21x³ -49x2≤0
-x(41-21x2 +49x)≤0
x*(41-21x2 +49x)⩾0
x⩾0
41-21x2 +49x⩾0
x≤0
41-21x²+49x≤0
x⩾0
x∈ [(49-√5845)/42, (49+√5845)/42]
x≤0
x∈ (-∞,(49-√5845)/42]∪[(49+√5845)/42,+∞)
x∈[0,(49+√5845)/42]
x∈(-∞,(49-√5845)/42]
x∈(-∞,(49-√5845)/42]∪[0,(49+√5845)/42]
1)28-7a^2= 7(4-a^2)=7(2-a)(2+a);
2)-11c^2+22c-11=-11(c^2-2+1)= -11(c-1)^2=-11(c-1)(c-1);
3)c^3a+8a=a(c^3+8)=a(c+2)(c^2-2c+4);
4)(y^2-1)^2-9= (y^2-1-3)(y^2-1+3)=(y^2-4)(y^2+2)=
=(y-2)(y+2)(y^2+2);
5) 3x^3-27x=0
3x(x^2-9)=0
3x(x-3)(x+3)=0
3x=0 => x=0
x-3=0 => x=3
x+3=0 =>x=-3
6) a^2+6a-40= (a+3)^2-49=(a+3)^2-7^2= (a+3-7)(a+3+7)=
=(a-4)(a+10).
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