Big Ideas Math: Modeling Real Life, Grade 7
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Big Ideas Math: Modeling Real Life, Grade 7 View details
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Exercise 20 Page 173

The word is divides the sentence into what should be on the left-hand side and what should be on the right-hand side of the equation.

Equation: 3* y=- 42
Solution: y=- 14

Practice makes perfect

We want to rewrite the word sentence as an equation and then solve it. We can do each of these things one at a time.

Equation

Let's consider the given word sentence!

3 times a number y is - 42.

Every equation has an equals sign and values or expressions on either side of it. Key phrases, such as is, is equal to, and equals tell us about the placement of the equals sign. 3times a numbery is - 42 ⇕ 3times a numbery = - 42 On the left-hand side we have one key word: times. This word tell us the operation that will be used in our equation. Times indicates multiplication. 3 times a numbery 3 * y On the right-hand side, there is only a constant. Putting these sides together, we have a complete equation. 3 * y = - 42

Solving the Equation

Finally, we can solve the equation using the Properties of Equality.
3* y=- 42
3* y/3=- 42/3
3/3* y=- 42/3
1* y=- 42/3
y=- 42/3
y=- 14