Ответ:
1) √11-5х = 1-х
-5х + х = 1 - √11
-4х = 1 - √11
х = - 1/4 + √11/4
х = -1 + √11 /4
х = 0,579156
x^2 + x = 0
x(x+1) = 0
x1 = 0
x2 = -1