Giúp mik làm bài 9 lớp 6 vs ah

`a) 4/x = 9/36 (x ne 0)`

`x = (4 . 36)/9 = 16`

Vậy `x = 16`

`b) x/3 = 5/15`

`x = (5 . 3)/15`

`x = 1`

Vậy `x = 1`

`c)- 3/x = 9/(-6)`

`x = (6 . 3)/9`

`x = 2`

Vậy `x = 2`

`d) 4/x = x/36 (x ne 0)`

`x^2 = 36 . 4`

`x^2 = 144`

`x^2 = (+-12)^2`

`x = 12` hoặc `x = -12`

Vậy `x in {+-12}`

`e) (x + 1)/7 = 28/(x + 1) (x ne - 1)`

`(x + 1)^2 = 7 . 28`

`(x + 1)^2=196`

`(x + 1)^3= (+-14)^2`

`x + 1=14` hoặc `x+1 = -14`

`x =14 - 1`            `x =- 14 - 1`

`x = 13`                `x =- 15`

Vậy `x in {13;-15}`

`f) (10 + x)/3= (17 + x)/4`

`(10 + x) . 4 = 3 (17 +x)`

`40 + 4x = 51 + 3x`

`4x - 3x = 51- 40`

`x = 11`

Vậy `x = 11`

`g) (40 + x)/6 = (77 - x)/4`

`4 (40 + x) = 6 (77 - x)`

`160 + 4x = 462 - 6x`

`4x + 6x = 462 - 160`

`10x = 302`

`x = 302 : 10 = 151/5`

Vậy `x = 151/5`