Question

Given the system of equations presented here:

3x + 5y = 29
x + 4y = 16

Which of the following actions creates an equivalent system such that, when combined with the other equation, one of the variables is eliminated?


Multiply the second equation by −1 to get −x − 4y = −16
Multiply the second equation by −3 to get −3x − 12y = −48
Multiply the first equation by −1 to get −3x − 5y = −29
Multiply the first equation by −3 to get −9x − 15y = −87

Answer 1

So they want one variable to be eliminated as stated by the question, yes? So what action essentially can we take so that when we add those two equations the x or y goes away entirely?

Answer 2

Ask yourself what plus what makes 3x, x, 5y or 4y go away

Answer 3

look at the second option,
−3x − 12y = −48
when added with the first equation,
3x + 5y = 29
will get rid of x