Х=(5+4у)/3
(5+4у)²/3-4у(5+4у)/3+4у²-5(5+4у)/3=1
(25+40у+16у²)/3-(20у+16у²)/3+4у²-(25+20у)/3=1
25+40у+16у²-20у-16у²+12у²-25-20у=3
12у²=3
у²=1\4
у1,2= +/- 1/2
х1=(5+4*1/2)/3=7/3
х2=(5+4*(-1/2))/3=3/3=1
х=(5-3у)\2
4(5-3у)²\4+12у*(5-3у)\2+8у²-5у=1
25-30у+9у²+30у-18у²+8у²-5у=1
у²+5у-24=0
D = 52 - 4·1·(-24) = 121
у1 = (-5 - √121 )/2= -8
у2 = (-5 + √121)/2 = 3
х1=(5-3*(-8))/2=(5+24)/2=29/2=14 1/2
х2=(5-3*3)/2=(5-9)/2=-4/2=-2
вроде так....