Trong các phép tính sau phép tính nào là phép tính sai ( giả thiết các phân thức có nghĩa ) :
A. $ \dfrac{7(x+7)(x-3)}{7(x+7)}=3-x $
B. $ \dfrac{\left( x+4 \right)(x+1)}{x+1}=x+4 $
C. $ \dfrac{x-2}{(x+3)(x-2)}=\dfrac{1}{x+3} $
D. $ \dfrac{2(x-3)(x+7)}{x+7}=2(x-3) $

Cho phân thức $ \dfrac{4x+3}{{{x}^{2}}-5} $ . Biến đổi phân thức để tử số trở thành $ 12{{x}^{2}}+9x $ . Khi đó mẫu số trở thành $ a{{x}^{3}}+bx $ trong đó $ a,b $ là các số nguyên. Khi đó $ a-b$ có giá trị bằng
A.$ 19 $.
B.$ 18 $.
C.$ 17 $.
D.$ 20 $.

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Detective books are _______ than science fiction ones.
A.more interesting
B.interesting
C.interestingly
D.interestinger

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
It is ______ in the city than it is in the country.
 
A.noisier
B.more noisier
C.noisy
D.noisily

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
These are new born.......................of our farm.
A.calves
B.calf
C.calfs
D.calfes

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
The tourist company was _______ down the street than I had thought.
A.farest
B.far
C.farer
D.farther

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
Are you proud ______ your country and its tradition ?
A.on
B.about
C.for
D.of

Giá trị của $ x $ thỏa mãn $ {{x}^{3}}+3{{x}^{2}}+3x+1=0 $ là
A. $ x=1 $ .
B. $ x=-2 $ .
C. $ x=0 $ .
D. $ x=-1 $ .

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to the following question.
People live in the city are................ about crime than the countryside ones.
A.worrieder
B.worried more
C.worrier
D.more worried

Choose the word whose underlined part differs from the other three in pronunciation
A.car
B.plane
C.famous
D.name