a)
[tex]7x + 2 = 30\\\\7x = 30-2\\\\7x = 28 \ \ /:7\\\\x = 4[/tex]
b)
[tex]8x-5-4x = 15\\\\4x = 15+5\\\\4x = 20 \ \ /:4\\\\x = 5[/tex]
c)
[tex]9x=5x-8\\\\9x-5x = -8\\\\4x = -8 \ \ /:4\\\\x = -2[/tex]
d)
[tex]8 + 3x = 7x - 4\\\\3x-7x =-4-8\\\\-4x = -12 \ \ /:(-4)\\\\x = 3[/tex]
e)
[tex]1 - 4x-5-5x+2 = 6x-6-8x-3\\\\-9x-2 = -2x-9\\\\-9x+2x = -9+2\\\\-7x = -7 \ \ /:(-7)\\\\x = 1[/tex]
f)
[tex]4(x-2)+x = 7\\\\4x-8+x = 7\\\\5x = 7+8\\\\5x = 15 \ \ /:5\\\\x = 3[/tex]