for math, when using substitutions and elimination...why do some systems have none or many solutions?

Question

a1234 · Answer

Because some equations are such that no one number can fit both the equations.

anonymous · Answer

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anonymous · Answer

many sol when lines overlap

anonymous · Answer

no sol parallel

anonymous · Answer

Some systems may intersect and some systems may not intersect because they are parallel or skewed.

anonymous · Answer

there are 4 anwsers...but how do i know which one is best...on a certain level, it seems all of your answers are a bit similar...except coolsday seemed to have provided a clearer explanation...how do i know which is correct.....

a1234 · Answer

As far as elimination and substitution go, it is mainly that no two numbers fit both the equations, but all the answers are correct in general.

anonymous · Answer

What type of systems are you dealing with? Lines or planes?