[latex] sqrt{x-7}=13-x[/latex]

[latex] sqrt{x-7}=13-x\ sqrt{x-7} geq 0= extgreater 13-x geq 0\13-x geq 0\x leq 13\\( sqrt{x-7})^2=(13-x)^2\x-7=169+x^2-26x\x^2-27x+176=0\D=(-27)^2-4*1*176=729-704=25=5^2\x_1=(27+5)/2=32/2=16( extgreater 13)\x_2=(27-5)/2=22/2=11( extless 13) [/latex]Ответ: 11