-10 = 2a - 4
-10 + 4 = 2a
-6 = 2a
-6/2 = a
-3 = a
=============
2(p + 1) = 16
2p + 2 = 16
2p = 16 - 2
2p = 14
p = 14/2
p = 7
==============
-3/4(x + 2) = 6
-3/4x - 6/4 = 6 ...multiply by -4
3x + 6 = -24
3x = -24 - 6
3x = -30
x = -30/3
x = -10
==================
-4.5(x - 8.9) = 12.6
-4.5x + 40.05 = 12.6
-4.5x = 12.6 - 40.5
-4.5x = - 27.45
x = -27.45/-4.5
x = 6.1