17Д
x³(x+1)-(x+1)=(x=1)(x³-1)=(x+1)(x-1)(x²+x+1)=(x²-1)(x²+x+1)
18A
(√7-2)²+4(√7-2)+4=7-4√7+4+4√7-8+4=7
20Г
(x-5)(x+5)/(x+5)-x(x-5)/(x-5)=x-5-x=-5
21Д
√3;1,3=√1,69;5/4=√1,5625
5/4;1,3;√3
39B
2|1-a|-|a|/2=2-2a+0,5a=2-1,5a a<0<br>89
√(x-3)²=|x-3|=|2,999-3|=0,001
92
22(5+√3)/(25-3)+8(√11-√3)/(11-3)-7(√11-2)/(11-4)=5+√3+√11-√3-√11+2=7