Question

evaluate the expression when a = -2 and c = 5.
c - 9a

Explanation:

Step1: Substitute the values of a and c

We are given the expression \( c - 9a \), and we know that \( a = -2 \) and \( c = 5 \). So we substitute these values into the expression: \( 5 - 9\times(-2) \).

Step2: Perform the multiplication

First, we calculate \( 9\times(-2) \). Remember that a positive number multiplied by a negative number gives a negative result, but here we have \( -9\times(-2) \)? Wait, no, the expression is \( c - 9a \), so it's \( 5 - (9\times(-2)) \). Let's compute \( 9\times(-2) = -18 \), so the expression becomes \( 5 - (-18) \).

Step3: Simplify the subtraction of a negative number

Subtracting a negative number is the same as adding its positive counterpart. So \( 5 - (-18) = 5 + 18 \).

Step4: Perform the addition

Now we add 5 and 18: \( 5 + 18 = 23 \).

Answer:

23