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.
Accepted Solution
A:
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 add 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: