Question

Найдите корень уравнения (x+3)^2=(x-9)^2

Answer 1

$(x+3)^2=(x-9)^2\\\\ (x+3)^2-(x-9)^2=0\\\\ ((x+3)-(x-9))*((x+3)+(x-9))=0\\\\ (x+3-x+9)*(x+3+x-9)=0\\\\ 12*(2x-6)=0\\\\ 2x-6=0\\\\ 2x=6\\\\ 2*x=2*3\\\\ x=3$
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Альтернатива:
$(x+3)^2=(x-9)^2\\\\ x^2+2*x*3+3^2=x^2-2*x*9+9^2\\\\ 6x+9=-18x+81\\\\ 6x+18x=81-9\\\\ 24x=72\\\\ 24*x=24*3\\\\ x=3$

Answer 2

x^2+6x+9=x^2-18x+81
24x=72
x=3
Ответ: 3