Ответ: L(x1,x2,x3)=(x1+2*x2+2*x3)²-4*(x2+1/2*x3)²+x3².
Объяснение:
L(x1,x2,x3)=(x1²+4*x1*x2+4*x1*x3)+4*x2*x3+4*x3²=[x1+2*(x1+x2)]²-4*(x2+x3)²+4*x2*x3+4*x3²=(x1+2*x2+2*x3)²-4*x2²-4*x2*x3=(x1+2*x2+2*x3)²-4*(x2²+x2*x3)=(x1+2*x2+2*x3)²-4*[(x2+1/2*x3)²-1/4*x3²]=(x1+2*x2+2*x3)²-4*(x2+1/2*x3)²+x3².
4х+3-10х-11=7+13-4х
-6х-8=20-4х
-6х+4х=20+8
-2х=28
х=-14
Решение во вложении: