=> y*(1+2+3+4+.........+10)=49,5

=> y*(10+1).10:2=49,5

=> y*11.10:2=49,5

=> y*110:2=49,5

=> y*110=49,5*2

=> y=99:110

=> y=0,9

dễ òm à

y+2 x y+3 x y+.....+10 x y=49,5

=>y x (1+2+3+....+10)=49,5

Tứ ->10 có:10-1+1=10(số hạng)

=>1+2+3+...+10=\(\frac{10x\left(10+1\right)}{2}=\frac{10x11}{2}=\frac{110}{2}=55\)

=>y x 55=49,5

=>y=49,5:55=>y=0,9

Ta có:

7 , 5 × y = 150 − 49 , 5 7 , 5 × y = 100 , 5      y = 100 , 5 : 7 , 5      y = 13 , 4

Vậy đáp án đúng điền vào ô trống là 13,4.

y+2xy+3xy+...+10xy=49,5

yx(1+2+3+4+...+10)=49,5

yx45                    =49,5

                          y= 49,5:45

                          y= 1,1

t tôi ik

7896  +  8765 = 16661

chúc bạn thành công!

7896 + 8765 = 16661

16661 bạn nhé !

b,tui ko bít

a)100-9:(372:3.y-1)-14=83

<=>100-9:(124y-1)-14=83

<=>86-9:(124y-1)=83

<=>9:(124y-1)=3

<=>124y-1=3

<=>124y=4

<=>y=\(\frac{1}{31}\approx0,3223\)

b)7260-120:24.y+924=528,3

<=>8184-5y=528,3

<=>5y=7655,7

<=>y=1531,14

c)2000-52:(615:3:y-15)-14=1984

<=>1986-52:(205:y-15)=1984

<=>52:(205:y-15)=2

<=>205:y-15=26

<=>205:y=41

<=>y=5

d)y+y.1/3+5/18=7/18

<=>4/3y=1/9

<=>y=1/12

e)13/15-(5/21+y)7/12=7/10

<=>7/12.(5/21+y)=1/6

<=>5/36+7/12y=1/6

<=>7/12y=1/36

<=>y=1/21\(\approx\)0,4762

h)y+2.y+3.y+...+10.y=49,5

<=>55y=49,5

<=>y=0,9

i)y.(1975/8.9+1885/9.10+1755/10.11+1579/11.12)=1/24

<=>7991,364899y=1/24

<=>y=33/6329161

tích nha mỏi tay quá

174x(23+7896:168)

= 174 x 70

= 12180

174x (23 + 7896 :168)

=174x (23 + 47)

=174 x 70

=12180

\(174× (23+7896:168)\)

\(=174× (23+47)\)

\(=174× 70\)

\(=12180\)

\(=174\times70=12180\)

174×(23+7896:168)

=174×(23+47)

=174×70

=12180