А -B = (√12 - √11) - (√13 - √12) = 2√12 - (√13 +√11) =
= 2√12 - √[24+2√11·13)] = 2√12 - √[24+2·√(12-1)(12+1)]=
= 2√12 - √[24 +2·√(12²-1)] = 2√12 - √[24 + 2·(12 -α)] =
α>0
=2√12 - √[4·(12 -α/2)] = 2√12 - 2√(12 - α/2) =
=2√12 - 2(√12 - β) = 2β >0
A > B
1) =6a^4-15a^3+6a
2) =2a²-7a+10a-35=2a²+3a-35
3) =36x²-27xy+4xy-3y²=36x²-23xy-3y²
4) =x³+2x²-3x-4x²-8x+12=x³-2x²-11x+12
Х+2 = +7 или х+2 = -7
х = 5 или х = -9