Consider the system of equations.

Question

{x−3y=4

{2x+y=1

Part A

To solve the system of equations, what step could be taken to eliminate one of the variables?

1. Multiply the top equation by 2 and add the result to the bottom equation.
2. Multiply the top equation by 3 and add the result to the bottom equation.
3. Multiply the bottom equation by 2 and add the result to the top equation.
4. Multiply the bottom equation by 3 and add the result to the top equation.

select one

Answer 1

x − 3y = 4 → equation (1)

2x + y = 1 → equation (2)

Multiply equation (2) by "3":

6x + 3y = 3 → equation (3)

Add equations (1) and (3):

x − 3y = 4

6x + 3y = 3

7x = 7 → solve to "x"

x = 1

Calculating "y" from equation (2):

y = 1 - 2x = 1 - 2 = -1

Answer 2

6x + 3y = 3

x - 3y = 4

7x = 7

x = 1

y= 1-2 = -1

that's the last choice, it works

the solution is (x,y) = (1,-1)

2(1)-1 = 1

1-(-3) = 4

plug that solution into either equation and it works.