Final answer:
To solve the system by substitution, we substitute the value of y from the second equation into the first equation and solve for x. Then, we substitute the value of x into either of the original equations to find y. The solution to the system is x = -5 and y = 50.
Step-by-step explanation:
To solve the system of equations using substitution, we will substitute the value of y from the second equation into the first equation. The second equation is y = -10x. Substituting this into the first equation, y = -9x + 5, we get -10x = -9x + 5. We can then solve for x by subtracting -9x from both sides of the equation to get -10x + 9x = 5. Simplifying this expression, we have -x = 5. Dividing both sides of the equation by -1, we find that x = -5.
To find the value of y, we substitute the value of x into either of the original equations. Let's use the second equation, y = -10x. Substituting x = -5, we get y = -10(-5), which simplifies to y = 50. Therefore, the solution to the system of equations is x = -5 and y = 50.