1.45
A = ( -6/11) . 7/10 . ( 11/-6 ) . (-20)
= ( -6/11) . ( 11/-6) . 7/10 . (-20)
= 1 . (-14)
= -14
B = (-1/9 ) . ( -17/29 ). 58/51
= (-1/9) . (-2/3)
= 2/27
C = (-3/7) . 5/11 + (-5/14) . 5/11
= 5/11 . [ -3/7 + ( -5/14) ]
= 5/11 . (-11/14)
= -5/14
D = ( $1$$\frac{1}{27}$ . 12/23 . 9/14 ) : (-3/23)
= ( 28/27 . 9/14 . 12/23 ) : (-3/23)
= ( 2/3 . 12/23 ) : ( -3/23 )
= 8/23 : ( - 3/23 )
= -8/3
1.46 . mik chịu
1.47.
a) 3/7x - 2/5x = -17/35
⇒ $\frac{3x}{7}$ + $\frac{-2x}{5}$ = $\frac{-17}{35}$
⇒ $\frac{5.3x}{35}$ + $\frac{7.(-2)x}{35}$ = $\frac{-17}{35}$
⇒ $\frac{5.3x+7.(-2)x }{35}$ = $\frac{-17}{35}$
⇒ $\frac{15x+(-14)x}{35}$ = $\frac{-17}{35}$
⇒ $\frac{15x-14x}{35}$ = $\frac{-17}{35}$
⇒ $\frac{1x}{35}$ = $\frac{-17}{35}$
⇒ 35 . $\frac{x}{35}$ = 35 . ( $\frac{-17}{35}$ )
⇒ x = 35 . ( $\frac{-17}{35}$ )
⇒ -17
b) (3/4x - 9/16).( 1/3 + -3/5 : x ) = 0
⇒ (3/4x - 9/16).( 1/3 + $\frac{-3/5}{x}$ ) = 0
⇒ ......... mik ko bt giải thik nha
⇒ 9/5
1.48
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