中一代數式問題,邊個可以幫我手?

1. n + 2 = 2n/9 - 1/3

n + 2 - 2 = 2n/9 - 1/3 - 2

n = 2n/9 - 7/3

n - 2n/9 = 2n/9 - 7/3 - 2n/9

7n/9 = -7/3

n = -7/3 X 9/7 = -3


2. 3t/4 = 4/3 (t - 7)

3t/4 = 4t/3 - 28/3

3t/4 - 4t/3 = 4t/3 - 28/3 - 4t/3

-7t/12 = -28/3

t = -28/3 X (-12/7)

t = 16


3. (x - 1)/5 - (4 - x)/2 - 2 = 0

10[(x - 1)/5 - (4 - x)/2 - 2] = 10(0) = 0

2(x - 1) - 5(4 - x) - 20 = 0

2x - 2 - 20 + 5x - 20 = 0

7x - 42 = 0

7x = 42

x = 6

1)n+2=2/9n-1/3
7/3=-7/9n
(7/3)(9/-7)=n
n=-3
2)3/4t=4/3(t-7)
3=(4/(3t-21))(4t)
3(3t-21)=16t
9t-63=16t
-7t=63
t=-9
3)x-1/5 - 4-x/2 - 2 = 0
(2x-2-20+5x)/10=2
7x-22=20
7x=42
x=6