{eq \x\le\ri(k)}=A'B'/AB=3AB/AB--->k=+-3--->k thuộc 2 trường hợp

th1:k=-3

k=(f-d)/f--->k.f=f-d--->(-3).f=f-12--->-4f=-12--->f=3

th2:k=3

k=(f-d)/f--->k.f=f-d--->3.f=f-12--->4f=-12--->f=-3

He always did well at school________having his early education disrupted by illness.

A. on account of        

B. in spite of         

C. in addition to   

D. even though

áp dụng định lí pytago

ab+ac=bc