Ответы на вопрос:
Log(5)(2-x)+0,5log(5)(4x-11)=0 {2-x> 0⇒x< 2 {4x-11≠0⇒x≠2,75 x∈(-∞; 2) log(5)(2-x)+log(5)√(4x-11)²=0 log(5)(2-x)+log(5)|4x-11|=0 log(5)[(2-x)*|4x-11|]=0 (2-x)*|4x-11|=1 x∈(-∞; 2)⇒|4x-11|=11-4x (2-x)(11-4x)=0 x=2не удов усл х=2,75 не удов усл ответ нет решения lgx²+lg(x+4)²≥-lg1/9 {x≠0 {x≠-4 x∈(-∞; -4) u (-4; 0) u (0; ∞) lg[x²(x+4)²]≥lg9 x²(x+4)²≥9 x²(x+4)²-9≥0 (x(x+4)-3)(x(x+4)+3)≥0 (x²+4x-3)(x²+4x+3)≥0 x²+4x-3=0 d=16+12=28 x1=(-4-2√7)/2=-2-√7 u x2=-2+√7 x²+4x+3=0 x1+x2=-4 u x1*x2=3⇒x1=-3 u x2=-1 + _ + _ + -2-√---2+√ ////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\///////////////////////////////// x∈(-∞; -2-√7] u [-3; -1] u [-2+√7; ∞)
(a+3)(a-6) =a² -6a +3a - 18 = a² -3a -18 (2x-1)(3x+2) = 6x² +4x -3x -2 = 6x² +x -2 (5x+3a)(x-2a) =5x² - 10ax +3ax -6a² =-6a² - 7ax + 5x²
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