Do system of equations x plus 7y equals 2 and x equals 9-7y?

Answer 1

There is no solution. Your system looks like this:
x + 7y = 2
x = 9 - 7y

The first can be rewritten as x = 2 - 7y,
and then join the two as 9 - 7y = 2 - 7y

Adding 7y to both yields 9 = 2 which is false, so there's no solution.

You can convert these to slope/intercept form as:
y = -x/7 + 2/7
y = -x/7 + 9/7

These are parallel lines, and will never intersect, so there is no solution that satisfies both equations.