4a²-20a+25+(9a-25)²+100x=4a²-20a+25+81a²-450a+625+100x= 85a²-470a+650+100x
85a²-470a+650+100x=0 | ÷5
17a²-94a+130+20x=0
4a²-20a+25+(9a-25)²+100x=4a²-20a+25+81a²-450a+625+100x= 85a²-470a+650+100x
85a²-470a+650+100x=0 | ÷5
17a²-94a+130+20x=0