Question

5x + 2y = 8
x + y = 4

If you want to solve the system of equations by addition, which of the following could you do?
a)Multiply the second equation by 5 and add.
b)Multiply the second equation by 2 and add.
c)Multiply the second equation by -2 and add.

Answer 1

If you're having trouble with a problem like this I'd try a process of elimination. Try the methods outlined in all 3 answers

Answer 2

to see which one would make a variable drop out thus allowing you to solve for the other variable

Answer 3

In this case, one of those methods will make the y-terms in the 2 equations add to 0

Answer 4

The correct answer is C, but you should try to figure out why.