1)543•9=4887
152•6=912
4887+912=5799
5799÷15=386,6
(4x+6x+18)/x(x+3)≥1
(10x+18)/x(x+3)≥1
(10x+18)/x(x+3) -1≥0
(10x+18-x²-3x)/x(x+3)≥0
(x²-7x-18)/x(x+3)≤0
x²-7x-18=0
x1+x2=7 U x1*x2=-18⇒x1=-2 U x2=9
x(x+3)=0⇒x=0 U x=-3
+ _ + _ +
________________________________________________
-3 -2 0 9
x∈(-3;-2] U (0;9]
X⁴-10x³+90x-81=0
(x⁴-81)-(10x³-90x)=0
(x²+9)(x²-9)-10x(x²-9)=0
(x²-9)(x²-10x+9)=0
x²-9=0
x₁=3
x₂=-3
x²-10x+9=0
По т. Виета
x₃=1
x₄= 9
Ответ: -3; 1; 3; 9.
Да.
(-7^2) = -7*-7=49.
<span>√49 = 7</span>