${(x-11+y)}^2+{(x-4+y)}^2=0$

1.

a) (1+2+3+...+90).(12.34-6.68):$\left(\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}\right)$

b)$\frac{{\displaystyle \frac{3}{7}}-{\displaystyle \frac{3}{11}}+{\displaystyle \frac{3}{13}}}{{\displaystyle \frac{5}{7}}-{\displaystyle \frac{5}{11}}+{\displaystyle \frac{5}{13}}}+\frac{{\displaystyle \frac{1}{2}}-{\displaystyle \frac{1}{3}}+{\displaystyle \frac{1}{4}}}{{\displaystyle \frac{5}{4}}-{\displaystyle \frac{5}{6}}+{\displaystyle \frac{5}{8}}}$

 Hobbies are activityies for entertenment. Hobby can cost you almost nothing (1)__________ in their free time. Sport provide other (2)__________hobbies. Cycling, running, tennis, table tennis are the sport that millions of people play during their free time.

 Some people's coin collections are wonderfull.There still hundereds of (3)__________, such as bottle collections, seashall collections, butterfly collections, and so on. For some people a hobby is a favourite (4)___________ like chess. In chess, we need two or more people (5)___________

1.$\frac{15}{19}.\frac{2}{3}-\frac{7}{19}.\frac{2}{3}+\frac{8}{3}.\frac{17}{19}$

(vẽ hình) cho tam giác ABC, M là trung điểm của BC. Trê tia đối của tia MA lấy điểm E sao cho ME=MA.