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5. Which does she like doing in her free time? => What
6. He always does the piano in the morning. => plays
5. Which -> What
4. does -> plays (play + nhạc cụ)
@sooyaaa
1. at -> in
2. like -> likes
3. goes usually -> usually goes
4. likes -> like.
1. I often watch TV at my free time. => in
2. He like surfing the Internet every day. => likes
3. He goes usually swimming on Sunday. => usually goes
4. They likes reading stories. => like
x.x + x = 272
x.x - 16.x + 17.x - 272 = 0
x.(x - 16) + 17.(x - 16) = 0
(x - 16)(x + 17) = 0
TH1: x - 16 = 0
x = 16
TH2: x + 17 = 0
x = -17
----------------------------------------------
\(\left(x-1\right)\left(\dfrac{1}{2}-x\right)=0\\ TH1:x-1=0\\ x=1\\ TH2:\dfrac{1}{2}-x=0\\ x=\dfrac{1}{2}\)
---------------------------------------------
x(x + 1) = 240
x.x + x = 240
x.x + x - 240 = 0
x.x - 15.x + 16.x - 240 = 0
x.(x - 15) + 16.(x - 15) = 0
(x + 16)(x - 15) = 0
TH1: x + 16 = 0
x = -16
TH2: x - 15 = 0
x = 15
\(F=\dfrac{1}{1\cdot2\cdot3}+\dfrac{1}{2\cdot3\cdot4}+...+\dfrac{1}{18\cdot19\cdot20}\\ =\dfrac{1}{2}\left(\dfrac{2}{1\cdot2\cdot3}+\dfrac{2}{2\cdot3\cdot4}+...+\dfrac{2}{18\cdot19\cdot20}\right)\\ =\dfrac{1}{2}\left(\dfrac{3-1}{1\cdot2\cdot3}+\dfrac{4-2}{2\cdot3\cdot4}+...+\dfrac{20-18}{18\cdot19\cdot20}\right)\\ =\dfrac{1}{2}\left(\dfrac{1}{1\cdot2}-\dfrac{1}{2\cdot3}+\dfrac{1}{2\cdot3}-\dfrac{1}{3\cdot4}+...+\dfrac{1}{18\cdot19}-\dfrac{1}{19\cdot20}\right)\\ =\dfrac{1}{2}\left(\dfrac{1}{1\cdot2}-\dfrac{1}{19\cdot20}\right)\\ =\dfrac{1}{2}\cdot\left(\dfrac{1}{2}-\dfrac{1}{380}\right)\\ =\dfrac{1}{2}\cdot\dfrac{189}{380}\\ =\dfrac{189}{760}\)
x.x + x = 272
x.x + x - 272 = 0
x.x + x.(17 - 16) - 272 = 0
x.x + 17.x - 16.x - 272 =0
x.(x + 17) - 16.(x + 17) = 0
(x - 16).(x + 17) = 0
TH1: x - 16 = 0
x = 16
TH2: x + 17 = 0
x = -17
1.watches
2.go
3.does
4.brush
5.get-does
1. watches
2. go
3. does
4. brush
5. get / does