Question

practice & problem solving
on p.206
13-16, explain how to get the variable alone in each equation.
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1. $8y=56$
2. $t\div15=3$
3. $u\div8=12$
4. $31y=310$

in 17-20, solve each equation.

1. $d\div2=108$
2. $7,200=800s$
3. $x\div3=294$
4. $99=3x$

solve and check
in 21 and 22, write a division equation and a multiplication equation to represent each problem.
solve

1. lolo typed 1,125 words in 15 minutes. let $w$ represent the number of words typed each minute. if lolo typed the same number of words each minute, how many words did she type in 1 minute?
2. in 12 weeks felipé earns $4,500 doing yard work. he earns the same amount each week. let $m$ stand for the amount earned each week. how much does felipé make in 1 week?
3. model with math abel has 3,330 toothpicks. he wants to use them all to make a floor mat with 18 equal rows. use the bar diagram to write a division equation. then solve the equation to find how many toothpicks abel should use in each row.
4. model with math emily took an airplane trip. her plane flew an equal number of miles each hour. let $m$ stand for the miles flown each hour. write an equation to represent one way you can find how many miles emilys plane flew each hour.

Explanation:

Step1: Isolate y via division

$\frac{8y}{8} = \frac{56}{8}$

Step2: Simplify to find y

$y = 7$

Step1: Isolate t via multiplication

$t \div 15 \times 15 = 3 \times 15$

Step2: Simplify to find t

$t = 45$

Step1: Isolate u via multiplication

$u \div 8 \times 8 = 12 \times 8$

Step2: Simplify to find u

$u = 96$

Step1: Isolate y via division

$\frac{31y}{31} = \frac{310}{31}$

Step2: Simplify to find y

$y = 10$

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Answer:

1. $y=7$
2. $t=45$
3. $u=96$
4. $y=10$
5. $d=216$
6. $s=9$
7. $x=882$
8. $x=33$
9. Division equation: $1125 \div 15 = w$; Multiplication equation: $15w=1125$; $w=75$
10. Division equation: $4500 \div 12 = m$; Multiplication equation: $12m=4500$; $m=375$
11. Equation: $3330 \div 18 = t$; $t=185$
12. Equation: $2184 \div 12 = m$; $m=182$