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-√7]------(-4)-------[-3]------------[-1]------(0)--------[-2+√7]-------------- ////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\///////////////////////////////// x∈(-∞;-2-√7] U [-3;-1] U [-2+√7;∞)
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Verified answer
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-√7]------(-4)-------[-3]------------[-1]------(0)--------[-2+√7]--------------
////////////////////////////////////\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\/////////////////////////////////
x∈(-∞;-2-√7] U [-3;-1] U [-2+√7;∞)