Question

question 3 of 25
what should be the first step in adding these equations to eliminate y?
12x - 2y = -1
+ 4x + 6y = -4
a. multiply the bottom equation by 3.
b. multiply the top equation by 4.
c. multiply the top equation by 3.
d. multiply the bottom equation by 12.

Explanation:

Step1: Analyze y - coefficients

Top equation: \(12x - 2y=-1\) (y - coefficient: \(-2\))
Bottom equation: \(4x + 6y=-4\) (y - coefficient: \(6\))

Step2: Find LCM of coefficients

LCM of \(2\) and \(6\) is \(6\). To make y - coefficients opposites (or same) for elimination, multiply top equation by \(3\):
New top equation: \(3(12x - 2y)=3(-1)\) → \(36x-6y = - 3\)
Now, y - coefficient of top is \(-6\), bottom is \(6\) (opposites, can add to eliminate y).

Answer:

C. Multiply the top equation by 3.