help vs nha
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42 lived here for 10 years
43 you work hard, you will be sacked
44 owner of this house
45 different from mine
X
1 It is famous for its long teaching history
2 in 1070
3 No, they didn't
4 It closed in 1802
5 Yes, they can
10-(5-x)=30+(2x-3)
10-5+x=30+2x-3
5+x=27+2x
x-2x=27-5
-x=22
x=-22
\(\left(\dfrac{1}{\sqrt{a}-1}-\dfrac{1}{\sqrt{a}}\right):\left(\dfrac{\sqrt{a}+1}{\sqrt{a}-2}-\dfrac{\sqrt{a}+2}{\sqrt{a}-1}\right)\)
\(=\left(\dfrac{\sqrt{a}}{\sqrt{a}\left(\sqrt{a}-1\right)}-\dfrac{\sqrt{a}-1}{\sqrt{a}\left(\sqrt{a}-1\right)}\right):\left(\dfrac{\left(\sqrt{a}+1\right)\left(\sqrt{a}-1\right)}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}-\dfrac{\left(\sqrt{a}+2\right)\left(\sqrt{a}-2\right)}{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}\right)\)
\(=\dfrac{\sqrt{a}-\sqrt{a}+1}{\sqrt{a}\left(\sqrt{a}-1\right)}:\left(\dfrac{a-1}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}-\dfrac{a-4}{\left(\sqrt{a}-1\right)\left(\sqrt{a}-2\right)}\right)\)
\(=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}:\dfrac{a-1-a+4}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}\)
\(=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}:\dfrac{3}{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}\)
\(=\dfrac{1}{\sqrt{a}\left(\sqrt{a}-1\right)}.\dfrac{\left(\sqrt{a}-2\right)\left(\sqrt{a}-1\right)}{3}\)
\(=\dfrac{\sqrt{a}-2}{3\sqrt{a}}\)
muỗi→trứng→ấu trùng→nhộng→muỗi trưởng thành
#chúc bạn học tốt!!
\(\left(x+1\right)\left(x-1\right)=x^2-x+x-1=x^2-1\)
\(\left(x-2y\right)\left(x+2y\right)=x^2+2xy-2xy-4y^2=x^2-4y^2\)
\(\left(x+1\right).\left(x-1\right)\)
\(=x^2-x+x-1\)
\(=x^2+\left(-x+x\right)-1\)
\(=x^2-1.\)
\(\left(x-2y\right).\left(x+2y\right)\)
\(=x^2+2xy-2xy-4y^2\)
\(=x^2+\left(2xy-2xy\right)-4y^2\)
\(=x^2-4y^2.\)
Chúc bạn học tốt!
Bài 6 :
a . 36 : 32 + 23 . 22
= 34 + 25
= 81 + 32
= 113
b .mình làm ở câu hỏi trc rồi ạ '-'
c . ( 23 . 17 - 23 . 15 ) : 42 - 1
= ( 23 . 2 ) : 16 - 1
= 24 : 16 - 1
= 16 : 16 - 1
= 1 - 1
= 0
d. Mình cx làm ở câu trước rồi đó '-'
Bài 6 :
c) = [ 23 ( 17 - 15 ) ] : 8 - 1
= ( 23 . 2 ) : 8 - 1
= 24 : 23 - 1
= 2 - 1
= 1