Question

How do you know that a system has no solution?

Answer 1

I can't graph them to find out.

Answer 2

what are the equations for the system?

Answer 3

a system has no solution if : the lines are parallel ... same slope and different y intercepts

Answer 4

or if at the end of the equations, once solved, do not equal.

Answer 5

I wasn't given any equations, but if it helps, I'm dealing with "Solving Systems of Equations in Three Variables"
I could give you an example of another problem if you'd like.

Answer 6

3 variables......ugh.....you been using elimination or substitution ?

Answer 7

substitution I believe.

Answer 8

where you plug one equation in the place of its same variable in another equation and solve? that is substitution right?
(I always get them mixed up.)

Answer 9

that is substitution.....do you want me to do one for you ?

Answer 10

Could you help me with this one?...

y = x + 2z
z = -1 -2x
x = y -14

Answer 11

x = y - 14
z = -1 - 2x

z = -1 - 2(y - 14)
z = -1 - 2y + 28
z = -2y + 27

y = x + 2z



y = y - 14 + 2(-2y + 27)
y = y - 14 - 4y + 54
y = -3y + 40
4y = 40
y = 10

x = y - 14
x = 10 - 14
x = - 4

y = x + 2z
10 = -4 + 2z
10 + 4 = 2z
14 = 2z
7 = z

check..
y = x + 2z
10 = -4 + 2(7)
10 = -4 + 14
10 = 10 (correct)

z = -1 - 2x
7 = -1 - 2(-4)
7 = -1 + 8
7 = 7 (correct)

answer is : x = -4, y = 10, and z = 7

Answer 12

Huh, I must've done something wrong because my answers were decimals. O.o

Answer 13

Huh, I must've done something wrong because my answers were decimals. O.o

Answer 14

Thank you for your help. ^^
Oh and one last question...Is it possible to just look at an equation and tell that there is no solution(s)?