Pr o b lem 2
Rew r itin g a Liter a l Eq u a tio n W ith O n ly Va r ia b les
Go t It? What equation do you get wh en you solve 2 t 5 r 1 px for x?
11. Use the justifications at the right to solve the equation.
2 t 5 r 1 px
Write the original equation.
2t 2
5 r 1 px 2
Subtract the sam e amount from each side.
2t 2
5 px
Simplify.
2t 2 r
t
2p 2
Pr o b lem 3
px
5 p
Divide each side by the same amount.
5 x
Simplify.
Rew r itin g a Geo m etr ic Fo r m u la
Go t It? What is the height of a trian gle that has an area of 24 in.2 and a base
with a length of 8 in.?
12. Circle the formula for the area of a trian gle.
A 5 12bh
r2
A5
d 5 rt
A5
w
13. Circle the rewritten formula you will use to find the height of the triangle.
5
P 2 2w
2
r5
d
A
h 5 2A
b
t5 r
Å
14. Now find the height of a triangle with an area of 24 in . 2 and a base of 8 in.
Pr o b lem 4
Rew r itin g a Fo r m u la
Go t It? Pacific gray whales m igrate ann ually from the waters near Alaska to th e
waters n ear Baja California, Mexico, and back. The whales travel a distance of
about 5000 m i each way at an average rate of 91 m i per day. About how m any days
does it take the whales to m igrate one way?
15. Write the formula that relates distance, rate, and time.
5
?
16. Circle what you are asked to find in the problem.
distance
Chapt er 2
rate
time
56
17. Complete the reasoning model below.
Think
Writ e
d
To isolate t, I divide each
rt
side of the formula by r.
Then I simplify.
Now I substitute 5000 for
d and 91 for r.
18. Simplify. The whales take about
Lesso n Check •
days to migrate one way.
Do y o u UN DERSTA N D?
Compare and Cont rast How is th e process of rewriting literal equation s sim ilar to
the process of solving equ ations in on e variable? How is it di erent?
19. When you rewrite a literal equation, you are solving it for one of the variables.
How is this process similar to solving an equation in one variable?
____________________________________________________________________
____________________________________________________________________
20. Describe one difference between rewriting a literal equation and solving an
equation in one variable.
____________________________________________________________________
____________________________________________________________________
M a th Su ccess
Ch eck off th e vocabulary words that you un derstan d.
literal equation
formu la
Rate how well you can rewrite litera l equa tions.
57
Lesson 2-5