Final answer:
The solution to the system of equations Y=3x+7 and Y=X-9 is x = -8 and y = -17. This is found by equating the Ys of the two equations, then solving for x and substituting it back in to find y.
Step-by-step explanation:
The solution of the system of equations Y=3x+7 and Y=X-9 can be found by setting the two equations equal to each other, since they both equal Y. This gives us 3x+7 = X-9. Solving for x, we subtract x from both sides to get 2x+7 = -9, and then subtract 7 from both sides to get 2x = -16. When we divide both sides by 2, we get x = -8. Now we can substitute x back into one of the original equations to find the corresponding y value. Using Y=X-9, we find that Y = -8-9, which simplifies to Y = -17. Therefore, the solution to the system of equations is x = -8 and y = -17.