Let's solve each of your questions one by one.
1. Total Earnings from Babysitting and Washing Cars
You earn $9 per hour for babysitting and $4 per hour for washing cars.
Given:
- \( b = 10 \) hours babysitting
- \( c = 10 \) cars washed
The total earnings can be calculated as follows:
\[ \text{Total Earnings} = 9b + 4c \]
Substituting the values:
\[ \text{Total Earnings} = 9(10) + 4(10) \]
Calculating:
\[ = 90 + 40 = 130 \]
So, your total earnings are $130.
2. Simplifying the Expression
The expression to simplify is:
\[ a - 5c + b - 7a - 4c + 2b \]
Combine like terms:
\[ = (a - 7a) + (b + 2b) + (-5c - 4c) \]
Calculating:
\[ = -6a + 3b - 9c \]
So, the simplified expression is \(-6a + 3b - 9c\).
3. Expanding Using the Distributive Property
To expand \(-2(3n + 3)\):
Using the distributive property:
\[ -2 \cdot 3n - 2 \cdot 3 \]
Calculating:
\[ = -6n - 6 \]
So, the expanded form is \(-6n - 6\).
4. Factoring Using the GCF
To factor \(12a - 30\):
First, find the greatest common factor (GCF). The GCF of 12 and 30 is 6.
Now, factor out the GCF:
\[ 12a - 30 = 6(2a - 5) \]
Thus, the factors are 6 and (2a - 5).
5. Simplifying the Expression
Now to simplify the expression:
\[ -5(0.2k + 1) - 2(0.4k - 2) \]
Distributing:
\[ = -5 \cdot 0.2k - 5 \cdot 1 - 2 \cdot 0.4k + 2 \cdot 2 \]
Calculating each term:
\[ = -1k - 5 - 0.8k + 4 \]
Combining like terms:
\[ = (-1k - 0.8k) + (-5 + 4) \]
Calculating further:
\[ = -1.8k - 1 \]
So, the simplified expression is \(-1.8k - 1\).
If you have any more questions or need further assistance, feel free to ask!