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Q8.

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Found in: Page 64

### Pre-algebra

Book edition Common Core Edition
Author(s) Ron Larson, Laurie Boswell, Timothy D. Kanold, Lee Stiff
Pages 183 pages
ISBN 9780547587776

# Simplify the expression.$\left(2r\right)\left(-5\right)$

$\left(2r\right) \left(-5\right) = -10 r$

See the step by step solution

## Step-1 – What are real numbers?

Real numbers are simply the combination of Whole numbers, Integers, Rational and Irrational numbers in the number system.

## Step-2 – Associative Property of Multiplication of Real Numbers:

Suppose a, b, and c is three real numbers.

Associative property of Multiplication

Property: $\text{(a} · \text{b)} · \text{c}=\text{a} · \left( \text{b} · \text{c} \right)$

If you are multiplying three real numbers, the product is always the same regardless of their grouping.

Example: $\text{(6} · \text{4)} · \text{3}=\text{6} · \left( \text{4} · \text{3} \right) = 72$

## Step-3:  Evaluate the expression 6(–3k).

Associative property of Multiplication states that if you are multiplying three real numbers, the product is always the same regardless of their grouping.

Property:$\text{(a} · \text{b)} · \text{c}=\text{a} · \left( \text{b} · \text{c} \right)$

So, we can multiply the numbers in any order and here a is a variable

$\begin{array}{l}\left(2r\right)\left(-5\right)\\ \left(2·-5\right)·r\text{AssociativePropertyofMultiplication}\\ -10r\end{array}$

$\left(2r\right) \left(-5\right) = -10 r$

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