a ) X x 6 - 4,99 = 25,01                                               b ) X : 6 = 7/4

     X x 6           = 25,01 + 4,99                                         X : 6 = 1,75

     X x 6           = 30                                                         X      = 1,75 x 6

     X                 = 30 : 6                                                    X      = 10,5

     X                 = 5

a) \(6x-4,99=25,01\)

\(6x=25,01+4,99\)

\(6x=30\)

\(x=5\)

vậy \(x=5\)

b) \(\frac{x}{6}=\frac{7}{4}\)

\(\Rightarrow4x=6.7\)

\(\Rightarrow4x=42\)

\(\Rightarrow x=10,5\)

vậy \(x=10,5\)

a) x*6-4,99=25,01

=>x*6=25,01+4,99

=>x*6=30

=>x=30:6

=>x=5

Vậy x=5

Tìm x : 

a) X x 6 - 4,99 = 25,01

X x 6 = 25,01 + 4,99

X x 6 = 30

X = 30 : 6

X = 5

b) \(x\times6=\frac{7}{4}\)

\(x=\frac{7}{4}\div6\)

\(x=\frac{7}{24}\)

~ happy new year ~

a:y x 6 = 25,01 + 4,99                                  

y x 6 = 30

y = 30 : 6

y = 5

b: y : 6 = 1,75

y = 1,75 x 6

y = 10,5

k mk nha bn

yx6=25,01+4,99

yx6=30

   y=30:6

   y=5
 

\(y=\left(25+4,99\right):6=\dfrac{2999}{600}\)

y x 6 - 4,99 = 25

y x 6=25+4,99=29,99

y=29,99:6=4.9983.......

y x 6 - 4,99 = 25

y x 6 = 25 + 4,99

y x 6 = 29,99

y = 29,99 : 6 

y = 4,998

\(\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\left(0,5-1\dfrac{3}{5}\right)\)

\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\left(\dfrac{1}{2}-\dfrac{8}{5}\right)\)

\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\dfrac{11}{10}\)

\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{33}{80}\)

\(\Rightarrow x:2,2=\dfrac{33}{80}:\dfrac{1}{6}\)

\(\Rightarrow x:2,2=\dfrac{99}{40}\)

\(\Rightarrow x=\dfrac{99}{40}\times2,2\)

\(\Rightarrow x=\dfrac{1089}{200}\)

=>(x:2,2)*1/6=-3/8(1/2-8/5)=33/80

=>x:2,2=99/40

=>x=1089/200

\(\Leftrightarrow4,5x-0,5x=2,6\)

\(\Leftrightarrow4x=2,6\)

\(\Leftrightarrow x=0,65\)

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chỉ cần lm 2 bài cuối thôi ạ

Bài 5:

a) \(\left(x-4\right)\left(x^2+4x+6\right)-x\left(x^2-6\right)=2\)

\(\Rightarrow x\left(x^2+4x+6\right)-4\left(x^2+4x+6\right)-x^3+6x=2\\ \Rightarrow x^3+4x^2+6x-4x^2-16x-24-x^3+6x=2\\ \Rightarrow-4x-24=2\\ \Rightarrow-4x=26\\ \Rightarrow x=-\dfrac{13}{2}\)

Bài 6:

\(a^3+b^3+3ab\\ =\left(a+b\right)\left(a^2+ab+b^2\right)+3ab\\ =a^2+ab+b^2+3ab\\ =a^2+4ab+b^2\)

25 x 18 + 50 x 5 + 72 x 25

=450 + 50 . 5 + 72 . 25

= 450 + 250+ 1800

= 2500

R

25 x 18 + 50 x 5 + 72 x 25

= 25 x 18 + 250 + 72 x 25

= 25 x 18 + 25 x 10 + 72 x 25

= 25 x ( 18 + 10 + 72 )

= 25 x 100

= 2500

25 x 18 + 50 x 5 + 72 x 25

=25 x 18 + 25 x 10 + 72 x 25

=25 x (18 + 10+ 72)

=25 x 100

=2500

a)  \(x^2+y^2=\left(x+y\right)^2-2xy=1^2-2.\left(-6\right)=13\)

    \(x^3+y^3=\left(x+y\right)^3-3xy\left(x+y\right)=1^3-3.\left(-6\right).1=19\)

\(x^5+y^5=\left(x^2+y^2\right)\left(x^3+y^3\right)-x^2y^2\left(x+y\right)=13.19-\left(-6\right)^2.1=211\)

b)  \(x^2+y^2=\left(x-y\right)^2+2xy=1^1+2.6=13\)

    \(x^3-y^3=\left(x-y\right)^3+3xy\left(x-y\right)=1^3+3.6.1=19\)

   \(x^5-y^5=\left(x^2+y^2\right)\left(x^3-y^3\right)+x^2y^2\left(x-y\right)=13.19+6^2.1=283\)