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Big Ideas Math: Modeling Real Life, Grade 7

BI

Big Ideas Math: Modeling Real Life, Grade 7 View details

Cumulative Practice

Exercise 9 Page 122

Remember, only like terms can be combined.

B

Before we try to simplify the given expression, let's use the Distributive Property so that we can get rid of the parentheses. This will also let us see the correct coefficients for any terms with variables.

7x-2(3x+6)

a+(- b)=a-b

7x+(- 2)(3x+6)

Distribute -2

7x+(- 2)(3x)+(-2)(6)

(- a)b = - ab

7x-6x-12

The next step in simplifying this expression is to identify which, if any, terms can be combined. Remember, only like terms — constant terms or terms with the same variable — can be combined. 7x - 6x - 12 In this case, we have two x-terms and one constant. Only the n-terms can be combined, so to simplify the expression we will combine like terms using subtraction. Let's do it! 7x-6x-12=x-12 This result corresponds to answer B.

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