100^n/5^2n-1*4^n-2=25<em /><em />^n*4^n/5^2n*4^n-2=5^2n*4^n/5^2n-1*4^n-2=5^(2n-2n+1)*4^(n-n+2)=5^1*4^2=5*16=80
(6x-5)^3=x^6
(6x-5)^3= (x^2)^3
6x-5=x^2
6x-5-x^2=0
x^2-6x+5=0
D= b^2-4ac= (-6)^2-4*1*5=16
x1= (6-4)/2=1
x2=(6+4)/2=5
Или по теореме Виета:
x1+x2= -b/a= 6(1+5=6)
x1*x2=c/a=5(1*5=5)
Ответ:1;5
X2-20x=-3x-21-x2
2x2-17x+21=0
D=(-17)2-4*2*21= 289 - 168=121
121 под корнем = 11
x1/2=17+ - 11 ; 4
x1 = (17+11): 4=7
x2 = (17-11) :4 = 1.5
25a-12a+4+35-14a=-a+39=39.1