Verified answer

Объяснение:

D(f):

[tex]12 + x - {x}^{2} > 0 \\ 12 + x - {x}^{2} = 0 \\ x = - 3 \\ x = 4 \\ x = ( - 3 \: \: . \: \: 4)[/tex]

[tex]x - 1 \geqslant 0 \\ x - 1 = 0 \\ x = 1 \\ x \geqslant 1[/tex]

D(f)=[1;4)

x=1

x=2

x=3

S=1+2+3=6