Each pair of points lies on a line with the given slope. find x and y.
(2,,8); slope=-2

I am slightly confused with your question. Are you looking for the equation or for x?

Anyway, here is both:

If you are finding the equation of the line, plug in your numbers in the equation y=mx+b. Use the point (2,4).
4=-2(2)+b
Solve for b.
4=-4+b
8=b
Then, put the slope and y-intercept in slope-intercept form.
y=mx+b.
y=-2x+8
Now you have the equation.

If you are solving for x, plug the point (x,8) in your equation.
y=-2x+8
8=-2x+8
Solve for x.
-2x=0
x=0

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post