Solve the system by substitution.

-2.5x + y = 13.5
2.25x - y = -12.25

We can solve the system by substituting y in terms of x from the first equation into the second equation.

From the first equation, we have y = -2.5x + 13.5.

Substituting this into the second equation, we get:

2.25x - (-2.5x + 13.5) = -12.25

Simplifying, we get:

2.25x + 2.5x - 13.5 = -12.25

Combine like terms:

4.75x - 13.5 = -12.25

Add 13.5 to both sides:

4.75x = 1.25

Divide both sides by 4.75:

x = 1.25 / 4.75 = 0.263

Now substitute this value of x into either of the original equations to find y.

Using the first equation:

-2.5(0.263) + y = 13.5
-0.658 + y = 13.5
y = 14.158

Therefore, the solution to the system of equations is x = 0.263 and y = 14.158.

The given system of equations is:

-2.5x + y = 13.5 ---(1)
2.25x - y = -12.25 ---(2)

We will solve this system by using the method of substitution. Let's solve equation (2) for y and substitute it into equation (1).

From equation (2), we have:
2.25x - y = -12.25

Rearranging this equation, we get:
y = 2.25x + 12.25

Now, substitute this value of y into equation (1):

-2.5x + (2.25x + 12.25) = 13.5

Simplifying:
-2.5x + 2.25x + 12.25 = 13.5
-0.25x + 12.25 = 13.5

Subtracting 12.25 from both sides:
-0.25x = 13.5 - 12.25
-0.25x = 1.25

Dividing by -0.25:
x = 1.25 / -0.25
x = -5

Now, substitute this value of x back into equation (2) to find the value of y:

2.25(-5) - y = -12.25

Simplifying:
-11.25 - y = -12.25

Adding 11.25 to both sides:
-y = -12.25 + 11.25
-y = -1

Multiplying by -1:
y = 1

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

To solve the system of equations by substitution, we need to isolate one variable in one of the equations and substitute it into the other equation.

Let's solve the first equation, -2.5x + y = 13.5, for y:
y = 2.5x + 13.5

Now we can substitute this expression for y into the second equation:
2.25x - (2.5x + 13.5) = -12.25

To simplify the equation, let's distribute the negative sign:
2.25x - 2.5x - 13.5 = -12.25

Combining like terms, we get:
-0.25x - 13.5 = -12.25

Next, let's isolate the x term by adding 13.5 to both sides of the equation:
-0.25x = -12.25 + 13.5

Simplifying, we have:
-0.25x = 1.25

To solve for x, divide both sides of the equation by -0.25:
x = 1.25 / -0.25

This gives us:
x = -5

Now that we know x, we can substitute it back into one of the original equations to find the value of y. Let's use the first equation:
-2.5(-5) + y = 13.5

Simplifying, we have:
12.5 + y = 13.5

Next, isolate y by subtracting 12.5 from both sides of the equation:
y = 13.5 - 12.5

This gives us:
y = 1

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