Answer:
9.
3 ( 1 - 3x ) = 2 (-4x + 7)
3 - 9x = -8x +14
-9x +8x = 14 - 3
-x = 11
x = -11
10.
-10 + x + 4 - 5 = 7x - 5
-10 +x -1 = 7x - 5
-11 + x = 7x - 5
-11 + 5 = 7x -x
-6 = 6x
x = -6/6
x = -1
11.
-8n + 4 ( 1 + 5n ) = -6n -14
-8n + 4 + 20n = -6n -14
12n +4 = -6n -14
12n + 6n = -14 -4
18n = -18
n = -18/18
n = -1
12.
-6n - 20 = -2n + 4 ( 1 - 3n)
-6n - 20 = -2n + 4 - 12n
-6n - 20 = -14n +4
-20 -4 = -14n +6n
-24 = 8n
n = -24/8
n = -3
13.
4n - 40 = 7 (-2n +2)
4n - 40 = -14n + 14
4n +14n = 14 +40
18n = 54
n = 54 / 18
n = 3
14.
7(5a - 4) -1 = 14 - 8a
35a -28 -1 = 14 - 8a
35a -29 = 14 - 8a
35a +8a = 14 +29
43a = 43
a = 43/43
a = 1
15.
-31 - 4x = -5 - 5 ( 1 + 5x)
-31 - 4x = -5 -5 - 25x
-31 - 4x = -10 -25x
-4x +25x = -10 +31
21x = 21
x = 21/21
x = 1
16.
38 +7k = 8 (k +4)
38 +7k = 8k + 32
38 - 32 = 8k -7k
k = 6
