Question

what is the value of a in the equation 3a + b = 54, when b = 9?
○ 15
○ 18
○ 21
○ 27

Explanation:

Step1: Substitute b=9 into the equation

We have the equation \(3a + b = 54\). Substitute \(b = 9\) into it, we get \(3a+9 = 54\).

Step2: Solve for 3a

Subtract 9 from both sides of the equation: \(3a=54 - 9\), so \(3a = 45\).

Step3: Solve for a

Divide both sides by 3: \(a=\frac{45}{3}=15\).

Answer:

15