`@` `\text {Ans}`
`\downarrow`
`1/5 \times x + 1/8 \times x = 3/4`
`x \times (1/5 + 1/8) = 3/4`
`x \times 13/40 = 3/4`
`x = 3/4 \div 13/40`
`x = 30/13`
BÀi 7 tìm số tự nhiên x biết
d) 35 : ( 2x x + 3) - 3 = 11 - 9 x 2,5 x 0,4; 8xx+ 4xx- 44=100; 5xx+ 3xx+ 4 = 68
e) ( x+1) + ( x+2) ....... + ( x + 211) = 23632
f) (1+3+5+7+........+2009) + x = 1010026
bài 8: tính hợp lí
( 98x 7676 - 9898 x 76) : ( 2+4 +6+........+200)
2/5xX-3/2=1/3
Tìm x: a, 213-2x X=47
b, 3x(x+1)-300=906
c,7/3-2/3xX=1/4
d,2/5xX+7/8=2
tìm x :a,5/9xX-1=8/9,b,X+Xx1/3:2/9+x:2/7=252,c,2/5+3/5xX=2/3
b)0,5xx+2/3xx+2/3=7/12
c)3/5-2/15:x=1/2
d)50%xx-2va1/2=2va5/6
e)(2va4/5xx-50):2/3-51
f)(4va1/2-2xx)x3va2/3=11/15
g)02/5-(2va1/2xx-3):15=1/10
h)(3/4+x)x1/1+5va1/6-1va1/6
b)0,5xx+2/3xx+2/3=7/12
c)3/5-2/15:x=1/2
d)50%xx-2va1/2=2va5/6
e)(2va4/5xx-50):2/3-51
f)(4va1/2-2xx)x3va2/3=11/15
g)02/5-(2va1/2xx-3):15=1/10
h)(3/4+x)x1/1+5va1/6-1va1/6
tìm X
3x(5xX-1) = 10
4x+7x x=2x11
5xx-x=16:4
36-8xX=26
Tìm X
