Question

Решите пж log5(x-7)+log5(x-2)=log5(x+5)

Answer 1

log5((x-7)(x-2))=log5(x+5). (x-7)(x-2)=x+5 x^2-7x-2x+14=x+5. x^2-10x+9=0 . D=100-4*9=64=8^2 .x1=(10+8)/2=9 x2=(10-8)/2=1