Solve the system by substitution.y, equals, 5, xy=5xy, equals, 9, x, plus, 4y=9x+4

The system of equations you provided seems to be incomplete or incorrectly formatted. A system of equations usually consists of two or more equations with the same variables. For example:

1. y = 5x
2. y = 9x + 4

If these are your equations, here's how you can solve them by substitution:

Step 1: Since y = 5x from the first equation, substitute y in the second equation with 5x:

5x = 9x + 4

Step 2: Solve for x:

Rearrange the equation to get all x terms on one side:

5x - 9x = 4

-4x = 4

Divide by -4:

x = -1

Step 3: Substitute x = -1 into the first equation to solve for y:

y = 5*(-1)

y = -5

So, the solution to the system of equations is x = -1 and y = -5.