1) (x-2)²-(x-7)(7+x)= x²+4-4x-(x²-49)= x²+4-4x-x²+49= 53-4x
2) (10+x)(x-10)-(x+3)²= x²-100-(x²+9+6x)= x²-100-x²-9-6x=-6x-109
3) (9-x)(x+9)-(x-7)²=81-x²-(x²+49-14x)= 81-x²-x²-49+14x= -2x²+32+14x
4) (3+x)²-(x-3)²= (3+x-(x-3))(3+x+x-3)= (3+x-x+3)*2x= 6*2x=12x
5) 2(a+4)²-(8+x)(x-8)= 2(a²+16+8a)-(x²-64)= 2a²+32+16a-x²+64= 2a²+16a-x²+96
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A) 2a²b²-6ab²+2a²b=
=2ab(ab-3b+a)
<span>25-c^2-это формула разности квадратов.
5*5=25. значит:
25-с²=(5-с)(5+с)</span>.
с^4-27с=c*c*c*c-27*c=c(c*c*c-27)=c(c³-27).
с*с*с*с=с^4