Question

Tìm x biết (1+2y)/18=(1+4y)/24=(1+6y)/6x

Answer 1

xét:\(\frac{1+2y}{18}=\frac{1+6y}{6x}=\frac{1+2y+1+6y}{18+6x}=\frac{2+8y}{18+6x}=\frac{2\left(1+4y\right)}{2\left(9+3x\right)}=\frac{1+4y}{9+3x}\) (t/c dãy tỉ số=nhau)

=>\(\frac{1+4y}{24}=\frac{1+4y}{9+3x}\Rightarrow24=9+3x\Rightarrow x=5\)

vậy x=5 thỏa mãn

Answer 2

Ta có: 1 + 2y/18 = 1 + 4y/24 = 1 + 6y/6x = 1 + 2y + 1 + 6y/18 + 6x = 2 + 8y/18 + 6x = 2(1 + 4y)/18 + 6x 
 \ 18 + 6x = 2 . 24 = 48
 \ 6x = 30
 \ x = 5

Answer 3

Ta có: 
(1) 1+2y/18 = 1+4y/24 
=> 24 + 48y = 18 + 72y 
<=> y=1/4 
(2) 1+4y/24=1+6y/6x 
Thay y=1/4 vào (2) ta tìm đc x=5 (thỏa)

Answer 4

ta co : 1+2y/18=1+4y/24

=> 24(1+2y)=18(1+4y)

=>24+48y=18+72y

=>24-18=72y-48y

=>6=24y

=>y=1/4 

thay y thanh 1/4 vao de bai ta co : 

1+1/2/18=1+1/24=(1+3/2)/6x

=>1/12=(5/2)/6x

=>12/(5/2)=6x

=>30=6x/x=5

vay x=5 va y=1/4