Question 46404
Since you have the solution to this system of equations, (-3, 4), you know that this point satisfies both equations.  Therefore, you can substitute the x- and y-cordinates of the point into the two equations and solve for the missing attribute (b and m) of the equations. Does this make sense?

5x+7y = b Substitute x = -3 and y = 4 from the point (-3, 4), and solve for b.
5(-3)+7(4) = b
-15 + 28 =b
b = 13 Done!

mx+y = 22 Substitute x = -3 and y = 4 from the point (-3, 4), and solve for m.
m(-3)+4 = 22 
-3m + 4 = 22 Subtract 4 from both sides.
-3m = 18 Divide both sides by -3
m = -6 Done!