4(2a + 3) = -3(a - 1) +31 - 11a
firstly, we open the parentheses at the both sides of the equation
4 * 2a + 4*3 = -3 *a - (-3) * 1 +31 -11a
8a + 12 = -3a + 3 + 31 - 11a
we collect the like terms
8a + 3a + 11a +12 = 3 + 31
11a + 11a +12 = 34
22a + 12 = 34
the next step is to isolate 22a then we have
22a = 34 -12
22a = 22
divide both sides by 22
22a/22 = 22/22
a = 1