Isolate the a. Note the equal sign, what you do to one side, you do to the other.
First, subtract 1.5a from both sides
12 + 1.5a (-1.5a) = 3a (-1.5a)
12 = 3a - 1.5a
12 = 1.5a
Isolate the a. Divide 1.5 from both sides
(12)/1.5 = (1.5a)/1.5
a = 12/1.5
a = 8
8 is your answer for a.
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Check: Plug in 8 for a.
12 + 1.5(8) = 3(8)
Simplify. Remember to follow PEMDAS.
12 + 1.5(8) = 24
12 + 12 = 24
24 = 24 (True)
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~Loliii is Waifu
Move terms
12+1.5a=3a
Collect the like terms
1.5a3a=-12
Divide both sides by -1.5
-1.5a=-12
a=8
