Question

How do you know when an equation has infinite solutions, or none?
2x + 9y=7
2x + 9y=11

Answer 1

use this website to graph both of them
www.desmos.com

Answer 2

try subtracting them

Answer 3

if there is 1 intersection point, they have one solution
if they're parallel lines, they have no solution
and if they overlap, then they have infinite number of solutions.

Answer 4

so how many solutions?

Answer 5

No solution?

Answer 6

correct!
why no solution?

Answer 7

Because the lines are parallel

Answer 8

good! so now do you understand?

Answer 9

Yes! Thanks so much :] Fan and medal :]

Answer 10

yw :)

Answer 11

if you subtract you get
0 = -4
which is obviously rubbish
this also indicates there is no solution

Answer 12

@Mehek14

Answer 13

what?

Answer 14

is there any way that I could solve it without using the site? In other words, mentally?

Answer 15

yes you can use the way @welshfella told you

Answer 16

So I subtract 2x by each side?

Answer 17

http://www.algebra.com/algebra/homework/Equations.faq.question.147147.html
this tells u all of the ways