30-25x = 100
tim x biet
a)2^x+2 -2^x=96
b)x-(50x/100+25x/200)=111/4
c) (x-5).30/100=200x/100+5
a) \(2^{x+2}-2^2=96\)
<=> \(2^x.2^2-2^x=96\)
<=> \(2^x\left(4-1\right)=96\)
<=> \(3.2^x=96\)
<=> \(2^x=32\)
<=> \(2^x=2^5\)
<=> x = 5
b, \(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\)
\(\Rightarrow x-\left(\frac{1x}{2}+\frac{1x}{8}\right)=\frac{45}{4}\)
\(\Rightarrow x-\left(\frac{4x}{8}+\frac{1x}{8}\right)=\frac{45}{4}\)
\(\Rightarrow x-\frac{5x}{8}=\frac{45}{4}\)
\(\Rightarrow\frac{8x}{8}-\frac{5x}{8}=\frac{45}{4}\)
\(\Rightarrow\frac{3x}{8}=\frac{45}{4}\Rightarrow x=\frac{45}{4}\div\frac{3}{8}=30\)
Vậy x = 30
a) -12.(x-5)+7.(3-x)=5
b) 30.(x+2)-6(x-5)-25x=100
VL, đây mà là toán lớp 5 á ??
a) -12.(x-5)+7.(3-x)=5
-12.x + 60 + 21 - 7.x = 5
( -12.x -7.x ) + ( 60 + 21 ) = 5
-19.x + 81 = 5
-19.x = 5 - 81
-19.x = -76
x = -76 : (-19)
x = 4
b) 30.(x+2)-6(x-5)-25x= 100
30x + 60 - 6x + 30 -25x = 100
( 30x - 6x -25x ) + ( 60 + 30 ) = 100
-1x + 90 = 100
-1x = 100 - 90
-1x = 10
x = 10 : ( -1 )
x = -10
tìm x biết rằng :
a) x - \(\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\) c) ( x - 5 ) . \(\frac{30}{100}=\frac{20x}{100}+5\)
a) x-\(\left(\frac{50x}{100}+\frac{25x}{200}\right)\)=\(11\frac{1}{4}\)
<=>x - \(\frac{1}{2}x-\frac{1}{8}x\)=\(\frac{11.4+1}{4}\)
<=>\(\frac{3}{8}x=\frac{45}{4}\)
<=>x=\(\frac{45}{4}:\frac{3}{8}\)
<=>x=30
Vậy x=30
c) (x-5).\(\frac{30}{100}\)=\(\frac{20x}{100}+5\)
<=>(x-5).\(\frac{3}{10}\)=\(\frac{x}{5}\)+5
<=>\(\frac{3x}{10}-\frac{15}{10}=\frac{x}{5}+5\)
<=>\(\frac{3x}{10}-\frac{x}{5}=5+\frac{15}{10}\)
<=>\(\frac{x}{10}=\frac{13}{2}\)
<=>x=\(\frac{13.10}{2}\)
<=>x=65
Vậy: x=65
\(x-\frac{25x}{100}=60-x+\frac{25x}{100}\)
<=>\(x+x-\frac{25x}{100}-\frac{25}{100}=60\)
<=>\(2x-\frac{50x}{100}=60\)
<=>\(\frac{150x}{100}=60\)
<=> 150x=6000
<=> x=40
Tính giá trị biểu thức
C= x^4 - 25x^3 + 25x^2 - 25x + 30 với x = 24
x=24 nên x+1=25
C=x^4-x^3(x+1)+x^2(x+1)-x(x+1)+30
=x^4-x^4-x^3+x^3+x^2-x^2-x+30
=-x+30
=30-24
=6
Tính M=x100-25x99+25x98-25x97+25x96-................-25x3+25x2-25x+25 tại x = 24
x=24
=> x+1=25
=> M=x100-(x+1)x99+(x+1)x98-(x+1)x97+(x+1)x96-...-(x+1)x3+(x+1)x2-(x+1)x+25
=x100-x100-x99+x99+x98-x98-x97+x97+x96-...-x4-x3+x3+x2-x2-x+25
=-x+25
=-24+25
=1
Vậy M=1.
tìm x
x - \(\dfrac{25x}{100}\)= 60 -x+\(\dfrac{25x}{100}\)
x-(60-x)=25x/100+25x/100
x-60+x=25x+25x/100
x-60+x=x(25+25)/100
x-60+x=x.50/100
x-60+x=x.50/50.2
x-60+x=x/2
.....
tới đây thui, mình ko biết làm nữa
ko biết là đúng hay sai đâu nhoa
Tìm x:
a) x - (\(\frac{50x}{100}\) + \(\frac{25x}{100}\)) = \(11\frac{1}{4}\)
b) (x-5) . \(\frac{30}{100}\) = \(\frac{200x}{100}\) + 5
- Help me!.
Tìm x:
a) \(x-\left(\frac{50x}{160}+\frac{25x}{200}\right)=11\frac{1}{4}\)
b)\(\left(x-5\right)\cdot\frac{30}{100}=\frac{200x}{100}+5\)
Giúp mình nhanh với, cảm ơn các bạn rất nhiều!