x²/25+(4x/5-12/5)²/4=1
x²/25+(4/5)²(x-3)²/4=1
x²/25+4(x-3)²/25=1
∴x²+4(x-3)²=25
即：5x²-24x+11=0
解得x1=(12+√89)/5 x2=(12-√89)/5