Ответ:

х^2-6х+9-х^2+10х-61=0

4х=52

х=13

Verified answer

[tex] {(x - 3)}^{2} = {x}^{2} - 10x + 61 \\ \\ {x }^{2} - 6x + 9 - {x}^{2} + 10x - 61 = 0 \\ \\ 4x - 52 = 0 \\ \\ 4x = 52 \\ \\ x = 13[/tex]