nữ = 23 ;nam=16

Giải chi tiết giupd mình

2

1 vế nhé

P = (82,54 x 94,7 - 85,56: 21,6) x (45 x 11 - 4500 x 0,1 - 45)

P = (82,54 x 94,97 - 85,56:21,6) x (45 x 11 - 45 x 10 - 45)

P = (82,54 x 94,97 - 85,56: 21,6) x 45 x (11 - 10 - 1)

P = (85,54 x 94,97 - 85,56:21,6) x 45 x (11 - 11)

P = (85,54 x 94,97 - 85,56:21,6) x 45 x 0

P = 0 

0 nhé

Cách 1 :
   105 : ( 3 x 5 )
= 105 : 15
= 7 



 

cách 1:

105:(3.5)=7

cách 2:

105(3.5)=105:3:5=7

Lời giải:

$\frac{x-1}{x+3}=\frac{x-2}{x+4}$ (điều kiện: $x\neq -3; -4$)

$\Rightarrow (x-1)(x+4)=(x-2)(x+3)$

$\Rightarrow x^2+3x-4=x^2+x-6$

$\Rightarrow 2x=-2$

$\Rightarrow x=-1$

1+2+3+4+5+6+7+8+9+10=55

55

Lời giải:

$\frac{x-5}{x+7}=\frac{1}{3}$ (điều kiện: $x\neq -7$)

$\Rightarrow 3(x-5)=x+7$

$\Rightarrow 3x-15=x+7$

$\Rightarrow 2x=22$

$\Rightarrow x=11$ (thỏa mãn)

A = \(\dfrac{2}{1\times3}\) + \(\dfrac{3}{3\times6}\) + \(\dfrac{4}{6\times10}\) + \(\dfrac{5}{10\times15}\) + \(\dfrac{6}{15\times21}\) + \(\dfrac{7}{21\times28}\)+\(\dfrac{8}{28\times36}\)

A = \(\dfrac{1}{1}\) - \(\dfrac{1}{3}\) + \(\dfrac{1}{3}\)- \(\dfrac{1}{6}\)+\(\dfrac{1}{6}\)-\(\dfrac{1}{10}\)+\(\dfrac{1}{10}\)- \(\dfrac{1}{15}\) + \(\dfrac{1}{15}\) - \(\dfrac{1}{21}\)+ \(\dfrac{1}{21}\)-\(\dfrac{1}{28}\)+\(\dfrac{1}{28}\)-\(\dfrac{1}{36}\)

A = \(\dfrac{1}{1}\) - \(\dfrac{1}{36}\)

A = \(\dfrac{35}{36}\)