1
(5-х)^2-(2-х)(3-х)
При Х=8
(5-8)^2-(2-8)(3-8)=(-3)^2-(-6)×(-5)=
=9-30= - 21
2
(х+5)^2-(3-х)(5-х)
При х=7
(7+5)^2-(3-7)(5-7)=12^2-(-4)(-2)=
=144-8=136
ответ: 1. (5-x)^2-(2-x)(3-x) = 25-x^2-(6-2x-3x+x^2)= 25-x^2-6+2x+3x-x^2= 19-2x^2+5x.
При x=8: 19-2•8^2+5•8= 19-2•64+40= 19-128+40= -128+59= -69.
2. (x+5)^2-(3-x)(5-x)= x^2+25-(15-3x-5x+x^2)= x^2+25-15+3x+5x-x^2= 10+8x.
При x=7: 10+8•7= 10+56=66.
