(16а^2-1)*(1/4а-1/4а+1-1)=(16а^2-1)*0=0
4(2-3х)+7(6х+1)-9(9х+4)=30
8-12х+42х+7-81х-36=30
-51х=30-(-21)
-51х=51
х=-1
Проверка: 4(2+3)+7(-6+1)-9(-9+4)=30
20-35-9*(-5)=30
-15+45=30
30=30
√ -56 - 15 Х= -Х
(√ -56-15х)² =( -Х)²
-56 -15х =Х ²
-Х ²-15х-56=0
Х²+15х+56=0
Д=√1=1
Х1=( -15+1):2= -7
Х2= ( -15 -1):2= -8
(x+14y)^2−(14x+y)^2 = (x+14y-14x-y)(x+14y+14x+y)=(13y-13x)(15y+15x)=13*15(y-x)(y+x)=195(y-x)(y+x)