Question

Solve systematic equation using both the substitution method and the addition method.
x=3y-7
2x-6y=-14

Answer 1

Could you kindly show me step by step?

Answer 2

I tried plugging what equals x into the second equation but I am stuck.

Answer 3

2(3y-7)-6y=-14
6y-14-6y=-14
-14 = -14.

Get it?

Answer 4

That's the substitution method?

Answer 5

Yes, I got that. How do I do the addition method?

Answer 6

isn't it 0=0 when you substitute x into the equation.

Answer 7

Yes, you are right. It is 0 = 0 for the substitution method. For the addition method:

x = 3y -7
2x - 6y = -14
------------
x - 3y = -7
2x - 6y = -14
------------
-2x + 6y = 14
2x - 6y = -14
------------
Then add, you get 0 = 0 as well.

Answer 8

Like I showed you earlier, -14 = -14 which tells us that both equations are the same regardless.

Answer 9

Oh okay, I understand. Thank you :)