b giúp mk câu hỏi của mkn nha

x+x+x+x+x=100⇔5x=100⇔x=100:5=20

\(x\) + \(x\) + \(x\) + \(x\) = 100

\(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\)1 + \(x\) \(\times\) 1 + \(x\) \(\times\) 1 =  100

\(x\) \(\times\) ( 1 + 1 + 1 + 1 + 1 ) = 100

\(x\) \(\times\) 5 = 100

\(x\)       = 100 : 5

\(x\)       = 20

\(x\) + \(x\) + \(x\) + \(x\) \(\times\) 5 = 200

\(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\)1 + \(x\) \(\times\) 5 = 200

\(x\) \(\times\) ( 1 + 1 + 1 + 5) = 200

\(x\) \(\times\)  8 = 200

\(x\)         = 200 : 8

\(x\)         = 25

(\(x\) + 1) + (\(x\) + 4) + ( \(x\) + 7) + (\(x\) + 10) = 62

 \(x\) + 1 + \(x\) + 4 + \(x\)+ 7 + \(x\) + 10 = 62

( \(x\) + \(x\) + \(x\) + \(x\) ) + ( 1 + 4 + 7 + 10) = 62

( \(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\) 1 + \(x\) \(\times\) 1) + 22 = 62

\(x\) \(\times\) ( 1 + 1 + 1 + 1)  + 22 = 62

\(x\)  \(\times\) 4 + 22 = 62

\(x\) \(\times\) 4 = 62 - 22

\(x\) \(\times\) 4 = 40

\(x\)         = 40 : 4

\(x\)         = 10

$x$ + $x$ + $x$ + $x$ = 100

$x$ $\times$ 1 + $x$ $\times$ 1 + $x$ $\times$1 + $x$ $\times$ 1 + $x$ $\times$ 1 =  100

$x$ $\times$ ( 1 + 1 + 1 + 1 + 1 ) = 100

$x$ $\times$ 5 = 100

$x$       = 100 : 5

$x$       = 20

$x$ + $x$ + $x$ + $x$ $\times$ 5 = 200

$x$ $\times$ 1 + $x$ $\times$ 1 + $x$ $\times$1 + $x$ $\times$ 5 = 200

$x$ $\times$ ( 1 + 1 + 1 + 5) = 200

$x$ $\times$  8 = 200

$x$         = 200 : 8

$x$         = 25

($x$ + 1) + ($x$ + 4) + ( $x$ + 7) + ($x$ + 10) = 62

 $x$ + 1 + $x$ + 4 + $x$+ 7 + $x$ + 10 = 62

( $x$ + $x$ + $x$ + $x$ ) + ( 1 + 4 + 7 + 10) = 62

( $x$ $\times$ 1 + $x$ $\times$ 1 + $x$ $\times$ 1 + $x$ $\times$ 1) + 22 = 62

$x$ $\times$ ( 1 + 1 + 1 + 1)  + 22 = 62

$x$  $\times$ 4 + 22 = 62

$x$ $\times$ 4 = 62 - 22

$x$ $\times$ 4 = 40

$x$         = 40 : 4

$x$         = 10

a, 200 - 3( x - 16 ) = 20

        3( x - 16 )     = 200 - 20 = 180

             x - 16     = 180 : 3 = 60 

                 x        = 60 + 16  =  76

b, 5 + 10 + 15 + .............. + 95 + 100 + 105 = 1200

c, x + ( 99 - 97 + 95 - 93 + ............ + 7 - 5 + 3 - 1 ) = 100

       x + ( 2 . 25 ) = 100

         x + 50       = 100

             x           = 100 - 50 = 50

****, thks 

\(a,12x=4x-30\Leftrightarrow8x=-30\Leftrightarrow x=-\dfrac{15}{4}\)

\(b,2x-5=x-1\Leftrightarrow2x-x=-1+5\Leftrightarrow x=4\)

\(c,2-5x=5x-10\Leftrightarrow-10x=-12\Leftrightarrow x=\dfrac{6}{5}\)

\(d,9x-6=1x-5\Leftrightarrow8x=1\Leftrightarrow x=\dfrac{1}{8}\)

\(e,2x-5=2x-1\Leftrightarrow2x-2x=-1+5\Leftrightarrow0x=4\) (Vô lí)\(\Rightarrow x\in\varnothing\)

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 

\(200:25-\left(12-x\right)=4\\ 8-\left(12-x\right)=4\\ 12-x=8-4\\ 12-x=4\\ x=12-4\\ x=8\\ ---\\ \left(x-10\right).5=100-20.4\\ \left(x-10\right).5=100-80=20\\ x-10=\dfrac{20}{5}=4\\ x=4+10=14\)

a)\(200:25-\left(12-x\right)=4\)

\(\Rightarrow8-\left(12-x\right)=4\)

\(\Rightarrow12-x=8-4\)

\(\Rightarrow12-x=4\)

\(\Rightarrow x=12-4\)

\(\Rightarrow x=8\)

b) \(\left(x-10\right)\cdot5=100-20\cdot4\)

\(\Rightarrow\left(x-10\right)\cdot5=100-80\)

\(\Rightarrow\left(x-10\right)\cdot5=20\)

\(\Rightarrow x-10=4\)

\(\Rightarrow x=10+4\)

\(\Rightarrow x=14\)

Hoctot

a: Ta có: \(100-7\left(x-5\right)=58\)

\(\Leftrightarrow7\left(x-5\right)=42\)

\(\Leftrightarrow x-5=6\)

hay x=11

b: Ta có: \(12\left(x-1\right):3=4^3+2^3\)

\(\Leftrightarrow12\left(x-1\right)=216\)

\(\Leftrightarrow x-1=18\)

hay x=19