\(\dfrac{54\times50+49\times100}{37\times38+126\times19}\)

\(=\dfrac{50\times\left(49\times2+54\right)}{38\times\left(63+37\right)}\)

\(=\dfrac{50\times152}{38\times100}\)

\(=\dfrac{25\times2\times4\times38}{38\times25\times4}\)

\(=2\)

a: 4/x=y/21=28/29

=>x=4:28/29=29/7; y=28/29x21=588/29

b: x/y=21/28

nên x/y=3/4

=>4x=3y

a ) x = 1 9 + 5 7 = 52 63 b ) x = 2 15 − 3 10 = − 1 6

c ) x = 2 45 − 1 9 = − 1 15 ; d ) x = − 3 7 − 4 5 − − 2 3 = − 59 105

a ) x = 2 45 − 1 9 = − 1 15 ; b ) x = − 3 7 − 4 5 − − 2 3 = − 59 105

\(a,\Rightarrow1-6x+9x^2-9x-9x^2=-29\\ \Rightarrow-15x=-30\Rightarrow x=2\\ b,\Rightarrow8x^3-12x^2+6x-1-x^2+4x-4=4x-25x^2-6\\ \Rightarrow8x^3+12x^2+6x+1=0\\ \Rightarrow\left(2x+1\right)^3=0\\ \Rightarrow2x+1=0\Rightarrow x=-\dfrac{1}{2}\)

A=19/23x46/74x37/19

A=1x2x1/1x2x1

A=2/2

A=1

A = 1919/2323 x 464646/747474 x 37/19

A = 19/23 x 46/74 x 39/19

A = 19x46x37/23x74x19

A = 1

 Vậy A = 1

lần lượt là:3920

6000

5600

6100

a 1000

b 48

a)  37 x 38 - 19 x 74 + 1000

= 37x19x2-19x2x37+1000

= 19x2x(37-37)+1000

= 38+1000

= 1038

b) 0,48x500-2,4x40x2

= 0,48x5x100-2,4x40x2

= 2,4x2x50-2,4x2x40

= 2,4x2x(50-40)

= 4,8x10

= 48