When solving an equation, Carmen's first step is shown below. Which property justifies Carmen's first step?

Original Equation:
Original Equation:
10, left parenthesis, minus, 4, x, squared, minus, 4, right parenthesis, plus, 5, equals, minus, 4, x, squared, minus, 10
10(−4x
2
−4)+5=
−4x
2
−10
First Step:
First Step:
10, left parenthesis, minus, 4, x, squared, minus, 4, right parenthesis, equals, minus, 4, x, squared, minus, 15
10(−4x
2
−4)=
−4x
2
−15

1 answer

Carmen's first step can be justified by using the Distributive Property.

In the original equation, Carmen is distributing the 10 to both terms inside the parentheses. Here's how it breaks down:

  1. The expression \( 10(-4x^2 - 4) \) can be expanded using the Distributive Property: \[ 10(-4x^2) + 10(-4) = -40x^2 - 40 \]

  2. When combined with the \( +5 \) from the original equation: \[ -40 + 5 = -35 \] Thus, we have: \[ -40x^2 - 35 \]

So, the statement \( 10(-4x^2 - 4) = -40x^2 - 40 \) and the following adding of 5 to -40 gives you -15, supporting the conclusion that: \[ 10(-4x^2 - 4) + 5 = -4x^2 - 15 \]

Therefore, the correct property that justifies Carmen's first step is the Distributive Property.