Question

In order to solve the following system of equations by addition, which of the following could you do before adding the equations so that one variable will be eliminated when you add them?





A. Multiply the top equation by 1/3
B. Multiply the top equation by 3 and the bottom equation by 4
C. Multiply the top equation by 3 and the bottom equation by 2
D. Multiply the top equation by
-3 and the bottom equation by 2

Answer 1

@johnweldon1993

Answer 2

Well if we multiply the top by -3 and bottom by 2..we would have

\[\large -3(4x - 2y = 7) = -12x + 6y = -21\]
and
\[\large 2(2x - 3y = 15) = 4x - 6y = 30\]

So if we were to add

Answer 3

Sorry, dunno why I wrote =15 in the picture...supposed to be 30

but doesn't change the answer :)

Answer 4

D?