Question

Question 3 of 10In order to solve the following system of equations by addition, which of thefollowing could you do before adding the equations so that one variable willbe eliminated when you add them?2x - 4y=56x-3y=10OA. Multiply the top equation by-2.B. Multiply the top equation by 3 and the bottom equation by 4.C. Multiply the top equation by -3.D. Multiply the top equation by -3 and the bottom equation by 2.

Answer 1

Given

2x - 4y = 5

6x - 3y = 10

To eliminate the first term of both equations, the first equation must have a similar x-term but with opposite sign. Therefore, we need the first equation so that its x-term is -6x. Divide it by the original first term to get the factor

$\frac{-6x}{2x}=-3$

Therefore, we nee to multiply the top equation by -3.