Question

2x +

YS
= 7
1
62
2y = 5
Which would be a more helpful for solving the system: adding the two
equations or subtracting one from the other? Explain your reasoning.
Solve the system without graphing. Show your reasoning.

Answer 1

subtracting one from the other

Explanation:

The equations are not well written. Let us assume the equations are:

2x + y = 7 .... 1

2x + 2y = 5 ....2

Looking at the two equations, using elimination method will be the best way to go.

Since the coefficient of the variable x are the same, we can take the difference of both equation to cancel out the variable x and get y as shown;

(2x-2x) + (y-2y) = 7-5

0 - y = 2

y = -2

Note that you can only subtract if the coefficient of the variables in both equations have the same coefficient (same sign) and add if they have different signs