Question

Solve the system using elimination. 3x – y = 28 3x + y = 14

Answer 1

Answer:

Step-by-step explanation:

Let 3x-y=28-----------(1)

Let 3x+y =14-----------(2)

(2)-(1)

3x-3x + y-(-y) =14-28

2y=-14

y=-14/2= -7

By adding 1 and 2

3x+3x+(-y)+(y) = 28+14

6x = 42

X=42/7=6

Answer 2

Answer:

x= 7, y= -7         or          (7, -7)

Step-by-step explanation:

3x-y=28

3x+y=14

because the y is opposite of each other in both equations you can cancel them out

3x=28

3x=14

next you add 3x to 3x, then 28 to 14 and get...

6x=42

next divide both sides by 6 and you get your answer for x...

x=7

now you must solve for y and you do this by substituting what you found for x in one equation it doesn't matter which because you'll get the same answer but you can check for both to make sure...

3(7)+y=14

21+y=14

y=-21+14

y=-7