(3х-1)^2+(4х+5)^2 = (5х-7)^2

9x²-6x+1+16x²+40x+25-25x²+70x-49=0
104x=23
x=23/104

9x^2-6x+1+16x^2+40x+25=25x^2-70x+49
-6x+1+40x+25=-70x+49
104x=23
x=23:104