Toán Lớp 6: a) 7/19×8/11+7/19×3/11+12/19
b) 9/5×2/7×5/9x(-14)
c) -9/16×8/15-7/16×9/15
Giúp mình với. Cảm ơn
Leave a reply
Register Now
Login
Lost Password
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Toán Lớp 6: a) 7/19×8/11+7/19×3/11+12/19
b) 9/5×2/7×5/9x(-14)
c) -9/16×8/15-7/16×9/15
Giúp mình với. Cảm ơn
Comments ( 2 )
a) $\dfrac{7}{19}$ $\times$ $\dfrac{8}{11}$ + $\dfrac{7}{19}$ $\times$ $\dfrac{3}{11}$ + $\dfrac{12}{19}$
= $\dfrac{7}{19}$ $\times$ ( $\dfrac{8}{11}$ + $\dfrac{3}{11}$ ) + $\dfrac{12}{19}$
= $\dfrac{7}{19}$ $\times$ $\dfrac{11}{11}$ + $\dfrac{12}{19}$
= $\dfrac{7}{19}$ $\times$ 1 + $\dfrac{12}{19}$
= $\dfrac{7}{19}$+ $\dfrac{12}{19}$
= $\dfrac{19}{19}$
= 1
b) $\dfrac{9}{5}$ $\times$ $\dfrac{2}{7}$ $\times$ $\dfrac{9}{5}$ $\times$ ( -14 )
= ( $\dfrac{9}{5}$ $\times$ $\dfrac{9}{5}$ ) $\times$ ( -14 ) $\times$ $\dfrac{2}{7}$ )
= 1 $\times$ ( -4 )
= -4
c) $\dfrac{-9}{16}$ $\times$ $\dfrac{8}{15}$ – $\dfrac{7}{16}$ $\times$ $\dfrac{9}{15}$
= $\dfrac{-72}{240}$ – $\dfrac{63}{240}$
= $\dfrac{-135}{240}$
= $\dfrac{-9}{16}$
Giải đáp ++ Lời giải và giải thích chi tiết:
a)
$\dfrac{7}{19}$ $\times$ $\dfrac{8}{11}$ + $\dfrac{7}{19}$ $\times$ $\dfrac{3}{11}$ + $\dfrac{12}{19}$
= ( $\dfrac{7}{19}$ + $\dfrac{12}{9}$ ) $\times$ ( $\dfrac{8}{11}$ + $\dfrac{3}{11}$ )
= $\dfrac{19}{19}$ $\times$ $\dfrac{11}{11}$
= $\text{1 $\times$ 1 }$
$\text{= 1 }$
b)
$\dfrac{9}{5}$ $\times$ $\dfrac{2}{7}$ $\times$ $\dfrac{5}{9}$ $\times$ $\text{(- 14 )}$
= ( $\dfrac{9}{5}$ x $\dfrac{5}{9}$ ) $\times$ ( $\dfrac{2}{7}$ $\times$ $\text{(- 14 )}$
$\text{= 1 $\times$ ( – 4 )}$
$\text{= – 4}$
c)
$\dfrac{-9}{16}$ $\times$ $\dfrac{8}{15}$ – $\dfrac{7}{16}$ $\times$ $\dfrac{9}{15}$
$\text{= $\dfrac{-9}{16}$ }$