test vaif thuw
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4
17 tháng 4 2023
a: góc A=180-60=120 dộ
=>góc EAB=60 độ=góc BAI
Xet ΔEAB và ΔIAB có
góc EAB=góc IAB
AB chung
EA=IA
=>ΔEAB=ΔIAB
=>BE=BI
=>AB là trung trực của IE
Chứng minh tương tự, ta được: AC là trung trực của IF
b: góc EAB=góc FAC=60 độ
=>góc EAB+góc BAI=góc FAC+góc IAC
=>góc EAI=góc FAI
Xét ΔEAI và ΔFAI có
AI chung
góc EAI=góc FAI
AE=AF
=>ΔEAI=ΔFAI
=>EI=FI
=>ΔIFE cân tại I
=>góc EIF=2*góc AIE
ΔEAI cân tại A
=>góc AIE=(180-60-60)/2=30 độ
=>góc EIF=60 độ
=>ΔIEF đều
c: góc AIE=góc AIF
=>AI là phân giác của góc EIF
mà ΔEIF đều
nên AI vuông góc EF
27 tháng 5 2023
33. The test was very long. We couldn’t do it in forty-five minutes.
A. We couldn’t do the test in forty-five minutes though it was long.
B. The test was too long for US to do in forty-five minutes.
C. The test was long enough for US to do in forty-five minutes.
D. Forty-five minutes is the time we needed to do the long test.
34. I failed the exam. My mother was disappointed.
A. I failed the exam, but my mother was disappointed.
B. I failed the exam, or my mother was disappointed.
C. I failed the exam, so my mother was disappointed.
D. I failed the exam although my mother was disappointed.
35. We started to play golf last month.
A. We have played golf since last month. B. We played golf since last month.
C. We have played golf for last month. D. We have started to play golf since last month.
36. “Close your books”, the teacher said to us.
A. The teacher told US close our books. B. The teacher told US to closing our books.
C. The teacher told US closing our books. D. The teacher told US to close our books.
GL
27 tháng 5 2023
33. The test was very long. We couldn’t do it in forty-five minutes.
A. We couldn’t do the test in forty-five minutes though it was long.
B. The test was too long for US to do in forty-five minutes.
C. The test was long enough for US to do in forty-five minutes.
D. Forty-five minutes is the time we needed to do the long test.
34. I failed the exam. My mother was disappointed.
A. I failed the exam, but my mother was disappointed.
B. I failed the exam, or my mother was disappointed.
C. I failed the exam, so my mother was disappointed.
D. I failed the exam although my mother was disappointed.
35. We started to play golf last month.
A. We have played golf since last month. B. We played golf since last month.
C. We have played golf for last month. D. We have started to play golf since last month.
36. “Close your books”, the teacher said to us.
A. The teacher told US close our books. B. The teacher told US to closing our books.
C. The teacher told US closing our books. D. The teacher told US to close our books.