What is the rule on why 5a + 9 = 3b becomes 5a/3 + 9/3 = b and not (5a + 9)/3 = b when solving for b? I'm very rusty at algebra and trying to learn the rule to avoid making the mistake of not splitting up the numerator into two separate fractions, which leads to the wrong answer. [In this case, the right answer ends up being 5a/3+3=b.]
5a + 9 = 3bSFtraveler wrote:What is the rule on why 5a + 9 = 3b becomes 5a/3 + 9/3 = b and not (5a + 9)/3 = b when solving for b?
This is the original equation.
Left Hand Side (LHS) is 5a + 9 and Right Hand Side (RHS) is 3b
Step 1: Multiple both sides by 1/3 (this also means "Divide both sides by 3")
Thus, (5a + 9) * (1/3) = 3b * (1/3)
Step 2: Open the brackets and make each term individual
Thus, (5a/3) + (9/3) = 3b/3
=> 5a/3 + 3 = b (Desired Answer)
















