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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Tìm y ∈ Z: a) y – 5 + (7 – 2y) = 20 b) (y -2) x (y + 1000) x (y + 27) = 0 c) (9 – y²) x (y + 1) = 0 d) 5y – 16 = 40 + y e) 30 x (y + 2)

Home/ Toán Lớp 6: Tìm y ∈ Z: a) y – 5 + (7 – 2y) = 20 b) (y -2) x (y + 1000) x (y + 27) = 0 c) (9 – y²) x (y + 1) = 0 d) 5y – 16 = 40 + y e) 30 x (y + 2)

Toán Lớp 6: Tìm y ∈ Z: a) y – 5 + (7 – 2y) = 20 b) (y -2) x (y + 1000) x (y + 27) = 0 c) (9 – y²) x (y + 1) = 0 d) 5y – 16 = 40 + y e) 30 x (y + 2)

Tháng Tám 22, 2022 Toán học 1 Comment 0 views

Toán Lớp 6: Tìm y ∈ Z:
a) y – 5 + (7 – 2y) = 20
b) (y -2) x (y + 1000) x (y + 27) = 0
c) (9 – y²) x (y + 1) = 0
d) 5y – 16 = 40 + y
e) 30 x (y + 2) – 6 x (y – 5) = 100
f) (y – 1) x (y – 3) = -1

Comments ( 1 )

  1. minhtuquynh
    minhtuquynh
    22 Tháng Tám, 2022 at 2:11 chiều
    Reply
    $ a) y-5+7-2y=20 ⇒ ( y -2y)+(-5+7)=20 ⇒ -y+2=20 ⇒ -y=20-2=18 ⇒ y=-18 $ 
    $ b) ( y-2)×(y+1000)×(y+27)=0 $ 
    $ ⇒ $ \(\left[ \begin{array}{l}y-2=0⇒y=0+2=2\\y+1000=0⇒y=0-1000=-1000\\y+27=0⇒y=0-27=-27\end{array} \right.\) 
    $ c) ( 9-y^2 ) × ( y+1)=0 $ 
    $ ⇒ $ \(\left[ \begin{array}{l}9-y^2=0⇒y^2=9⇒y=±3 \\y+1=0⇒y=0-1=-1\end{array} \right.\) 
    $ d) 5y – 16 = 40 + y $ 
    $ ⇒ 5y-y=40+16=56⇒4y=56⇒y=56:4=14 $
    $ e) 30 × (y + 2) – 6 × (y – 5) = 100 ⇒ 30y + 60 – 6y – 30 = 100 ⇒ ( 30y – 6y ) + ( 60-30)=100 $
    $ 24y+30=100⇒y=(100-30):24=70:24=35/12 $ 
    $ f) ( y-1)×(y-3)=-1 $ 
    $ TH1 : $ \(\left[ \begin{array}{l}y-1=1 ⇒ y=1+1=2\\y-3=-1 ⇒y=-1+3=2 \end{array} \right.\)
    $ TH2 : $ \(\left[ \begin{array}{l}y-1=-1⇒y=-1+1=0\\y-3=1⇒y=1+3=4\end{array} \right.\) 

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222-9+11+12:2*14+14 = ? ( )

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