Question

tìm abcd,biết abcd-bcdx2=ac

ai nhanh mk k cho

Answer 1

mik xin sua lai cho nay

a*990+b*99+c*10+d=bcd*2

a*990+b*99+c*10+d=(b*100+c*10+d)*2

a*990+b*99+c*10+d=b*200+c+20+d

a*990=b*101

Ban cu the ma lam nha

Answer 2

abcd -bcd*2 = ac

(a*1000+b*100+c*10+d) - bcd*2 = a*10+b

a*1000+b*100+c*10+d=a*10+b+bcd*2

a*990+b*99+c*10+d=bcd*2

a*990+b*99+c*10+d=b*100+c*10+d

      a*990=b

Mik nghi chi duoc vay thui hihi