Which statement correctly explains how Dana can solve the following system of linear equations for x using the elimination method?

4x+8y=20

-4x+2y = - 30

Add the two equations, solve for y, and then substitute - 1 for y to find x.

Multiply the bottom equation by - 4, solve for y, and then substitute - 1 for y to find x.

Multiply the bottom equation by - 1, combine the two equations, solve for y, and then substitute 1 for y to find x.

Multiply the two equations, solve for y, and then substitute 1 for y to find x.

Question

Mathematics

Shirley

3 January, 08:20

Which statement correctly explains how Dana can solve the following system of linear equations for x using the elimination method?

4x+8y=20

-4x+2y = - 30

Add the two equations, solve for y, and then substitute - 1 for y to find x.

Multiply the bottom equation by - 4, solve for y, and then substitute - 1 for y to find x.

Multiply the bottom equation by - 1, combine the two equations, solve for y, and then substitute 1 for y to find x.

Multiply the two equations, solve for y, and then substitute 1 for y to find x.

+5

Answers (1)

Know the Answer?

Virginia Terry · Answer 1

1. The correct statement is the first one, which is: Add the two equations, solve for y, and then substitute - 1 for y to find x.

2. Therefore, you have the following system of equations:

4x+8y=20

-4x+2y = - 30

3. When you a dd the two equations, and clear the variable "y", you obtain:

10y=-10

y=-1

4. Now, you must substitute - 1 for y (y=-1) to find x, as below:

4x+8y=20

4x+8 (-1) = 20

4x-8=20

4x=20+8

4x=28

x=28/4

x=7