How to divide exponents

Help Questions

PSAT Math › How to divide exponents

Questions 1 - 10
1

If , then

Cannot be determined

Explanation

Start by simplifying the numerator and denominator separately. In the numerator, (c3)2 is equal to c6. In the denominator, c2 * c4 equals c6 as well. Dividing the numerator by the denominator, c6/c6, gives an answer of 1, because the numerator and the denominator are the equivalent.

2

Explanation

The key to this problem is understanding how exponents divide. When two exponents have the same base, then the exponent on the bottom can simply be subtracted from the exponent on top. I.e.:

Keeping this in mind, we simply break the problem down into prime factors, multiply out the exponents, and solve.

3

Simplify

\dpi{100} \small \frac{20x^{4}y^{-3}z^{2}}{5z^{-1}y^{2}x^{2}}=

\dpi{100} \small \frac{4x^{2}z^{3}}{y^{5}}

\dpi{100} \small {4x^{5}y^{-2}}

\dpi{100} \small 15x^{2}y^{2}z^{2}

\dpi{100} \small 15x^{-2}y^{-2}z^{-2}

None

Explanation

Divide the coefficients and subtract the exponents.

4

54 / 25 =

25

5

10

50

54 / 5

Explanation

25 = 5 * 5 = 52. Then 54 / 25 = 54 / 52.

Now we can subtract the exponents because the operation is division. 54 / 52 = 54 – 2 = 52 = 25. The answer is therefore 25.

5

Simplify_exponent_7-11-13

a3(b3√b)(c)

(b3)/(a3c2)

(b3√b)/(a3c)

(b7)/(a3c)

a2b3√c

Explanation

Simplify_exponent_2_7-11-13

Simplify_exponent_4_7-11-13

6

For all real numbers n, (2_n_ * 2) / (2_n_ * 2_n_) =

2_n_/2_n_

2_n_

21 – n

2_n_ – 1

2

Explanation

(2_n_ * 2) / (2_n_ * 2_n_) simplifies to 2/2_n_ or 21/2_n_.

When dividing exponents with the same base, you subtract the divisor from the dividend, giving 21–n.

7

Simplify the following expression: (x2y4)/(x3y3z2)

xy/z2

xz2/y

y/xz2

z2xy

Explanation

According to the rules of exponents, ax/ay = ax-y

In this expression, we can follow this rule to simplify x2/x3 and y4/y3

x2–3 = x–1 = 1/x. y4–3 = y1 = y.

Therefore, y/xz2

8

Half of the radioactive nuclei of a substance decays in a week. If a sample started with 1010 nuclei, how many have decayed after 28 days?

9.375 x 109

1010

106

6.25 x 108

28 x 1010

Explanation

If half of the sample decays each week: 1/2 is left after one week, 1/4 is left after two weeks, 1/8 is left after three weeks and 1/16 is left after four weeks (28 days.) That means that 15/16 has decayed. 15/16 x 1010 = 9. 375 x 109

9

If x7 / x-3/2 = xn, what is the value of n?

10/2

21/2

-21/2

11/2

17/2

Explanation

x7 / x-3/2 = x7 (x+3/2) based on the fact that division changes the sign of an exponent.

x7 (x+3/2) = x7+3/2 due to the additive property of exponent numbers that are multiplied.

7+3/2= 14/2 + 3/2 = 17/2 so

x7 / x-3/2 = x7+3/2 = x17/2

Since x7 / x-3/2 = xn, xn = x17/2

So n = 17/2

10
  1. 5. Simplify the problem (x4y2/x5)3

x3y6

x4/y6

y6/x3

y5/x

x/y

Explanation

Properties of exponents suggests that when multiplying the same base, add the exponents, when dividing, subtract the exponents on bottom from those on top, and when raising an exponent to another power, multiply the exponents. Remember that (x4/x5) = x–1 = 1/x; Still using order of operations (PEMDAS) we get the following:(x4y2/x5)3= (y2/x)3 = y6/(x3).

Page 1 of 2
Return to subject