Question

Solve using substitution method:
9x - 7y = 8

Answer 1

I don't know how to do substitution.

Answer 2

there's supposed be another equation....

Answer 3

is that algebra.

Answer 4

yeah hey where is the pther equation.

Answer 5

oh woops
9x - 7y = 8
18x - 14y = -7

Answer 6

9x - 7y = 8
9x = 8 + 7y
x = (8 + 7y)/9

Substitute into the second equation:

18 [(8 + 7y)/9] - 14y = -7
2(8 + 7y) - 14 y = -7
16 + 14y - 14 y = -7
16 = -7 which cannot happen

There is no solution to this system of equations.
The graphs of the two lines are parallel and there is no common solution.

Answer 7

See graph at the link for visual confirmation.

http://www.wolframalpha.com/input/?i=%289x+-+7y+%3D+8%29+and+%2818x+-+14y+%3D+-7%29