To get rid of a square, take the square root; to get rid of a cube, take the cube root.
Most people find it easier to work with negative exponents if they are written as fractions, as shown below:
Only appears as an answer choice, so (D) is correct. You could check this by using your calculator to compute (0.5)−4.
H
To get rid of decimals in a fraction, multiply the top and bottom by the smallest power of 10 you can. For example, if you
need to move a decimal over 2 places, multiply the top and bottom by 100.
Set up a direct proportion:
Cross-multiply:
If you have trouble setting up the proportion, you can use the answer choices to your advantage and take an educated guess.
Since 2.2 pounds equals a kilogram, a pound must be a little less than a kilogram. Of the possible answers, and are
over and and seem too small. But is just under so it should be the correct answer.
50.
B
Picking Numbers is even sweeter when the test maker narrows down what kinds of numbers you can use.
Pick Numbers. Remember to check all the answer choices—since you are looking for the choice that is negative for all
possible values of r and p, you’ll need to eliminate answer choices that are only negative for some values of r and p. Say r =
1 and p = −1.
51.
(A) (1)(−1) + 2 = 1
(B) −|1(−1)| = −|−1| = −1
(C) 12 (−1)^2 − 10 = 1 − 10 = −9
