Question

Substitution method?

Answer 1

What about it?

Answer 2

3x + 3y = 10
-9x - 9y = -30

Answer 3

What happens if we divide the second equation by -3?

Answer 4

sub·sti·tu·tion [sùbstə tsh'n]
(plural sub·sti·tu·tions)
noun
1. act of replacing: the replacement of somebody or something with another, especially one team member with another on the field
2. somebody or something that replaces: somebody or something that replaces another, especially one team member who replaces another on the field
3. mathematics replacement of mathematical element: the replacement of one mathematical element with another of equal value
4. logic replacement of logical expression: the replacement of one logical expression with another, or a replaced logical expression

Answer 5

@soty2013 , you're so cute the way you define terms as a first step. I respect that.

Answer 6

i need help cliffsedge

Answer 7

If we divide the second equation by -3 we end up with

3x + 3y = 10, thus we see that both equations are equal. Therefore, there is no need to proceed any further. Nor is it necessary to substitute anything.

Answer 8

Then how would I get ehe solution to the system?

Answer 9

Anytime you get a result such as this where both equations are the same, it means that any combination of x and y will work for both equations.

Answer 10

Where do those two lines intersect, @xKingx ?

Answer 11

The question is, "Do we even have two lines?".

Answer 12

Seems to me like we have two equations, but only one line.

Answer 13

Perhaps. If a line is length with no thickness, it is possible for two lines to occupy the same space.
(I don't think quantum mechanical rules apply to geometric objects).

Answer 14

I would rather see it as we have two equations that represent the same line.

Answer 15

I'm cool with equivalent systems too.

Answer 16

Alright then

Answer 17

Try graphing the lines for both of those equations, @xKingx