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Example
Read the problem. Identify what you need to know. Then use the information in
the problem to solve.
Given the equation
√
2
x
_
3
y
=
8, which of the following represents
y
in terms of
x
?
A
y
=
x
_
32
C
y
=
x
_
96
B
y
=
√
8
x
_
3
D
y
=
√
2
x
_
3
Step 1
What information is given? Are any of the following involved: earlier
quantities, answer choices that are easy to test, or inverse operations?
An equation is given. Because I need to solve for a variable, I will use inverse
operations.
Step 2
How will working backward help solve this problem?
I’ll use inverse operations to “undo” operations and isolate the variable
y
.
Step 3
How can you check your answer? What is the correct answer?
I can “work forward” by beginning with my answer and seeing if I arrive at
the same result given in the problem. Choice C is correct.
Test-Taking Strategy
Test-Taking Tip
Strategies for Working
Backward
In certain math problems,
you are given information
about an end result, but you
are asked to find out
something that happened
earlier. In other problems, it
can be faster to work from
the answer choices, instead
of from the problem. Finally,
you’ll sometimes need to use
inverse operations, which is
a specific way of working
backward. You can work
backward to solve all of
these kinds of problems.
Read the problem. Identify what you need to know. Then use the information in the problem to solve.
An object is shot straight upward into the air with an initial speed of 800 feet per second. The height
h
that the
object will be after
t
seconds is given by the equation
h
= -
16
t
2
+
800
t
. When will the object reach a height of
10,000 feet?
A
10 seconds
C
100 seconds
B
25 seconds
D
625 seconds
Answer the questions below.
a.
What information is given? Are any of the following involved: earlier quantities, answer choices that are easy to
test, or inverse operations?
b.
How will working backward help solve this problem?
c.
How can you check your answer?
d.
What is the correct answer?
Apply the Strategy
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