x + 25 =25+27
a) 2019/2020 x 4/11 + 2019/2020 x 5/11 + 2019/2020 x 2/11
b) 17/14 x 25/27 - 1/14 x 25/27 - 2/14 x 25/27
\(a.=\dfrac{2019}{2020}\times\left(\dfrac{4}{11}+\dfrac{5}{11}+\dfrac{2}{11}\right)\\ =\dfrac{2019}{2020}\times1=\dfrac{2019}{2020}\\ b.=\dfrac{25}{27}\times\left(\dfrac{17}{14}-\dfrac{1}{14}-\dfrac{2}{14}\right)\\ =\dfrac{25}{27}\times1=\dfrac{25}{27}\)
tính hợp lý
a. (- 25) + (- 72) x 25 + (- 25) x 27
b. - 36 x 45 + 4 x 15 x (- 9) - 2 x 18 x (- 40)
c. 37 x ( 25 + 37) - 27 x ( 37 + 25)
= ( -25) x 1 +72 x (-25) + (-25) x27
= (- 25) x ( 1 + 72 + 27 )
= (-25) x 100
=-2500
b
c 37 x ( 25 + 37 ) - 27 x ( 37 + 25 )
= 37 x 25 + 37 x 37 -27x37 -27x25
= ( 37 x25 -27x25 )+(37x37-27+37)
=25 x ( 37 -27 ) + 37 x (37 - 27)
= 25 x10 + 37x10
= 250 + 370
= 770
tính hợp lý
a. (- 25) + (- 72) x 25 + (- 25) x 27
b. - 36 x 45 + 4 x 15 x (- 9) - 2 x 18 x (- 40)
c. 37 x ( 25 + 37) - 27 x ( 37 + 25)
a) =-25.( 1+72+27)
=-25.100= - 2500
b) = -36.45 + (-36) . 15 - (-36) . 40
= - 36. ( 45+15-40)
= -36 . 20= -720
c) =37.62 - 27 .62
= 62. ( 37 - 27 )
= 62 . 10
= 620
\(\dfrac{29-x}{21}\)+\(\dfrac{27-x}{23}\)+\(\dfrac{25-x}{25}\)+\(\dfrac{23-x}{27}\)+\(\dfrac{21-x}{29}\)=\(\dfrac{(29-x+1}{21}\)+\(\dfrac{(27-x+1)}{23}\)+\(\dfrac{(25-x+1)}{25}\)+\(\dfrac{(23-x+1)}{21}\)=-5 +5
GIẢI nốt hộ mình với ạ
\(\dfrac{29-x}{21}\)+\(\dfrac{27-x}{23}\)+\(\dfrac{25-x}{25}\)+\(\dfrac{23-x}{27}\)=-4
\(\Leftrightarrow\dfrac{29-x}{21}+1+\dfrac{27-x}{23}+1+\dfrac{25-x}{25}+1+\dfrac{23-x}{27}+1=0\)
\(\Leftrightarrow\dfrac{50-x}{21}+\dfrac{50-x}{23}+\dfrac{50-x}{25}+\dfrac{50-x}{27}=0\)
\(\Leftrightarrow\left(50-x\right)\left(\dfrac{1}{21}+\dfrac{1}{23}+\dfrac{1}{25}+\dfrac{1}{27}\ne0\right)=0\Leftrightarrow x=50\)
\(\dfrac{29-x}{21}+\dfrac{27-x}{23}+\dfrac{25-x}{25}+\dfrac{23-x}{27}=-4\\ \Leftrightarrow\left(\dfrac{29-x}{21}+1\right)+\left(\dfrac{27-x}{23}+1\right)+\left(\dfrac{25-x}{25}+1\right)+\left(\dfrac{23-x}{27}+1\right)=0\\ \Leftrightarrow\dfrac{50-x}{21}+\dfrac{50-x}{23}+\dfrac{50-x}{25}+\dfrac{50-x}{27}=0\\ \Leftrightarrow\left(50-x\right)\left(\dfrac{1}{21}+\dfrac{1}{23}+\dfrac{1}{25}+\dfrac{1}{27}\right)=0\\ \Leftrightarrow50-x=0\left(vì.\dfrac{1}{21}+\dfrac{1}{23}+\dfrac{1}{25}+\dfrac{1}{27}\ne0\right)\\ \Leftrightarrow x=50\)
Tim x biet
x-(-25-17-2x)=6+x
45-/-27-(-25)-x/=7+27
Tính nhanh: (25 x 4 + 27 x 5) x (100 - 25 x 4)
(25* 4+ 27* 5 )* (100-25 *4 )
=275 *(25*4 ) -100
=275* 0
=0
Lời giải:
$(25\times 4+27\times 5)\times (100-25\times 4)=(25\times 4+27\times 5)\times 0$
$=0$
( 25 x 4 + 27 x 5 ) x ( 100 - 25 x 4 )
= ( 25 x ( 4 + 5 )) x ( 100 - 100 )
= ( 25 x 9 ) x 0
= 225 x 0
= 0
học tốt nha
3.54 X 73 + 0.23 X 25 + 3.54 X 27 +0.77 X 25
3.54 X 73 + 0.23 X 25 + 3.54 X 27 +0.77 X 25
= 3.54X(73+27)+25X(0.23+0.77)
=354+25
=400
3,54.73+0,23.25+3,54.27+0,77.25
=(3,54.73+3,54.27)+(0,23.25+0,77.25)
=3,54.(73+27)+25.(0,23+0,77)
=3,54.100+25.1
=379
3,54 x 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25
3,54 x 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25
= 3,54 x ( 73 + 27 ) + 25 x ( 0,23 + 0,17 )
= 3,54 x 100 + 25 x 0,4
= 354 + 10
= 364
=3.54x(73+27)+25x(0.23+0.17)
=3.54x100+25x0.4
=354+10
=364
(k mk nha bn )
Trả lời
3,54 x 73 + 0,23 x 25 + 3,54 x 27 + 0,17 x 25
=3,54 x ( 73 + 27 ) + 25 x ( 0,23 + 0,17 )
= 3,54 x 100 + 25 x 0,4
= 354 + 10
= 364