a)(y+2):5-5x5=378
(y+2):5-25=378
(y+2):5=378+25
(y+2):5=403
(y+2)=403x5
y+2=2015
y=2015-2
y=2013
(y+2):5-5.5=378
(y+2):5-25=378
(y+20)=378+25
(y+2)=403
(y+2)=403.5
y+2=2015
y=2015-2
y=2013
a) \(\left(y+2\right):5-5.5=378\)
\(\left(y+2\right):5-25=378\)
\(\left(y+2\right):5=378+25\)
\(\left(y+2\right):5=403\)
\(y+2=403.5\)
\(y+2=2015\)
\(y=2015-2\)
\(y=2013\)
a) (y + 2):5 - 5.5 = 378
(y + 2):5 - 25 = 378
(y + 2):5 = 403
y + 2 = 2015
y = 2013
b) (7,56 . 0,99 + 7,56 . 0,01) . (y + 2) = 18,9
7,56 . (0,99 + 0,01) . (y + 2) = 18,9
7,56 . 1 . (y + 2) = 18,9
y + 2 = \(\frac{5}{2}\)
\(\Rightarrow y=\frac{5}{2}-2=\frac{1}{2}\)
c)
\(\left(y+\frac{1}{1.2}\right)+\left(y+\frac{1}{2.3}\right)+....+\left(y+\frac{1}{2013.2014}\right)=\frac{2013}{2014}\)
\(\left(y+y+y+....+y\right)+\left(\frac{1}{1.2}+\frac{1}{2.3}+....+\frac{1}{2013.2014}\right)=\frac{2013}{2014}\)
\(2013y+\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+.....+\frac{1}{2013}-\frac{1}{2014}\right)=\frac{2013}{2014}\)
\(2013y+\frac{2013}{2014}=\frac{2013}{2014}\)
=> 2013y = 0
=> y = 0
b) \(\left(7,56.0,99+7,56.0,01\right).\left(y+2\right)=18,9\)
\(\left(7,56.\left(0,99+0,11\right)\right).\left(y+2\right)=18,9\)
\(\left(7,56.1\right).\left(y+2\right)=18,9\)
\(7,56.\left(y+2\right)=18,9\)
\(y+2=18,9:7,56\)
\(y+2=2,5\)
\(y=2,5-2=0,5\)
Tìm y biết:
a)
( y + 2 ) : 5 - 5 . 5 = 378
y + 2 : 5 - 25 = 378
y + 2 : 5 = 378 + 25
y + 2 : 5 = 403
y + 2 = 403 . 5
y + 2 = 2015
y = 2015 - 2
y = 2013
b)
( 7, 56 . 0,99 + 7,56 . 0,01).(y+2) =18,9
( 7,56 . ( 0,99 + 0,01) .(y+2)=18,9
( 7,56 . 1) . ( y + 2 ) = 18,9
7,56 . ( y + 2 ) = 18,9
y + 2 = 18,9 : 7,56
y + 2 = 2,5
y = 2,5 - 2
y = 0,5
Ủng hộ :)
