Big Ideas Math Algebra 2, 2014
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Big Ideas Math Algebra 2, 2014 View details
Maintaining Mathematical Proficiency
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Exercise 10 Page 1

Think of a numerical expression that involves both addition and multiplication.

See solution.

We are asked to give an example to show why the order of operations is important when evaluating a numerical expression. Then, we are also asked if the order of transformations of figures is important. Let's discuss these things one at a time.

Order of Operations for Numerical Expressions

The order of operations is extremely important when evaluating a numerical expression. Let's see an example. 15+21* 2 We will calculate the value of the above expression by following the correct order of operations. Multiplication comes before addition.
15+21* 2
15+42
57
We found that the value of the expression is 57. Now, let's see what happens if we try to calculate the value by following the incorrect order of operations, adding and then multiplying.
15+21* 2
36* 2
72
We have incorrectly found that the value of the expression is 72. We see that the order of the operations is important to obtain the correct answer.

Order of Transformations of Figures

The order of transformations of figures is also important. Consider a triangle whose vertices are A(1,1), B(3,3), and C(1,5).

Let's translate the above triangle 4 units to the right and 1 unit up, and then reflect it in the x-axis.

We see that the resulting triangle has vertices (5,- 2), (7, - 4), and (5,- 6). Let's now apply the same transformations but in a different order. We will reflect △ABC in the x-axis, and then translate 4 units to the right and 1 unit up.

We see that the resulting triangle has vertices (5,0), (7,- 2), and (5, - 4). Therefore, we do not obtain the same result if we do not follow the same order of transformations.