a)\(\frac{45,2}{Y}+\frac{57,8}{Y}-\frac{71,8}{Y}\)=4,8
\(\frac{\left(45,2+57,8\right)-71,8}{Y}\)=4,8
=\(\frac{103-71,8}{Y}=4,8\)
\(\frac{31,2}{Y}=4,8\)
Y=\(\frac{31,2}{4,8}\)
Y=6,5.
b)107,8-\(\frac{Y}{9,5}\)=29,2
\(\frac{Y}{9,5}\)=107,8-29,2
\(\frac{Y}{9,5}\)=78,6
Y=78,6 x 9,5
Y=746,7
Bt2
a)175,84 x 3 -173,4+175,84 x 7 -62,6
=175,84 x (3+7) - (173,4+62,6)
=175,84 x 10 -236
=1758,4-236
=1522,4
b)521,12 x 5 -42,14 x 50+521,12 x 5 -42,14 x 50
=2(521,12 x 5 -42,14 x 50)
= 2 x (5 x (521,12 -42,14 x 10))
=2 x (5 x 99,72)
=2 x 498,6
=997,2.
Cho xin nhá :))