3 (-1-а)-20 = 9
-3-3а-20 = 9
-3а = 9+20+3
-3а = 32
а = - (32/3)
6(4-x)+3=3
24 - 6x = 3-3
-6x = -24
x = 4
3x-10=2+6(5+4x)
3x - 10 = 2 + 30 + 24x
3x - 24x = 32 + 10
-21x = 42
x = -2
4(7+x) - 3x = 7
28 + 4x -3x = 7
x = 7 - 28
x = -21
(x-5)(x+5) = (x-3)^2 +2
x^2 - 5^2 = x^2 - 6x + 9 + 2
6x = 9+2+25
6x = 36
x = 9
(x+6)^2 = (x-4)(x+4)-8
x^2 + 12x + 36 = x^2 - 4^2 - 8
12x = - 16 - 8 - 36
12x = - 60
x = -5