State whether the following equations are true for the given values of the variables.
`5-4r=9` for `r= -1`

Answer

To determine whether the equation \(5 - 4r = 9\) is true for the given value of \(r = -1\), we will follow these steps:

### Step 1: Substitute the value of \(r\) into the equation
We start with the equation:
\[ 5 - 4r = 9 \]
Now, substitute \(r = -1\) into the equation:
\[ 5 - 4(-1) = 9 \]

### Step 2: Simplify the left-hand side (LHS)
Now, we simplify the left-hand side:
\[ 5 - 4(-1) = 5 + 4 \]
Here, we used the fact that multiplying two negative numbers results in a positive number.

### Step 3: Calculate the result
Now, we calculate:
\[ 5 + 4 = 9 \]

### Step 4: Compare LHS with right-hand side (RHS)
Now we compare the left-hand side with the right-hand side:
\[ LHS = 9 \quad \text{and} \quad RHS = 9 \]

### Step 5: Conclusion
Since \(LHS = RHS\), we conclude that the equation \(5 - 4r = 9\) is true for \(r = -1\).

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