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4 votes
Which expression is equal to 4mn^8/28m^5n^3 ?

n^5/

7 m^4
n^5/ 7 m^5
7 m^5/ n^4
7 n^5/ m^4

1 Answer

5 votes

(-4mn)284(m2n3)/28m4n5(mn)2/28(m2n2)5/(4m2n3)2

Final result :

2560m298n298

————————————

49

Step by step solution :

Step 1 :

Equation at the end of step 1 :

((m2)•(n3)) ((mn)2) (((m2)•(n2))5)

((((((-4mn)284)•———————————)•(m4))•(n5))•———————)•——————————————

28 28 ((22m2•(n3))2)

Step 2 :

m10n10

Simplify ——————

24m4n6

Dividing exponential expressions :

2.1 m10 divided by m4 = m(10 - 4) = m6

Dividing exponential expressions :

2.2 n10 divided by n6 = n(10 - 6) = n4

Equation at the end of step 2 :

((m2)•(n3)) ((mn)2) m6n4

((((((-4mn)284)•———————————)•(m4))•(n5))•———————)•————

28 28 16

Step 3 :

m2n2

Simplify ————

28

Equation at the end of step 3 :

((m2)•(n3)) m2n2 m6n4

((((((-4mn)284)•———————————)•(m4))•(n5))•————)•————

28 28 16

Step 4 :

m2n3

Simplify ————

28

Equation at the end of step 4 :

m2n3 m2n2 m6n4

((((((-4mn)284)•————)•m4)•n5)•————)•————

28 28 16

Step 5 :

5.1 Negative number raised to an even power is positive

For example let's look at (-7)6 , where (-7) , a negative number, is raised to 6 , an even exponent :

(-7)6 can be written as (-7)•(-7)•(-7)•(-7)•(-7)•(-7)

Now, using the rule that says minus times minus is plus, (-7)6 can be written as (49)•(49)•(49) which in turn can be written as (7)•(7)•(7)•(7)•(7)•(7) or 76 which is positive.

We proved that (-7)6 is equal to (7)6 which is a positive number

Using the same arguments as above, replacing (-7) by any negative number, and replacing the exponent 6 by any even exponent, we proved which had to be proved

5.2 4 = 22 (-4)284 = (22)284 = 2568

Equation at the end of step 5 :

m2n3 m2n2 m6n4

((((2568m284n284 • ————) • m4) • n5) • ————) • ————

28 28 16

Step 6 :

Multiplying exponential expressions :

6.1 m284 multiplied by m2 = m(284 + 2) = m286

Multiplying exponential expressions :

6.2 n284 multiplied by n3 = n(284 + 3) = n287

Dividing exponents :

6.3 2568 divided by 22 = 2(568 - 2) = 2566

Equation at the end of step 6 :

2566m286n287 m2n2 m6n4

(((———————————— • m4) • n5) • ————) • ————

7 28 16

Step 7 :

Multiplying exponential expressions :

7.1 m286 multiplied by m4 = m(286 + 4) = m290

Equation at the end of step 7 :

2566m290n287 m2n2 m6n4

((———————————— • n5) • ————) • ————

7 28 16

Step 8 :

Multiplying exponential expressions :

8.1 n287 multiplied by n5 = n(287 + 5) = n292

Equation at the end of step 8 :

2566m290n292 m2n2 m6n4

(———————————— • ————) • ————

7 28 16

Step 9 :

Multiplying exponential expressions :

9.1 m290 multiplied by m2 = m(290 + 2) = m292

Multiplying exponential expressions :

9.2 n292 multiplied by n2 = n(292 + 2) = n294

Dividing exponents :

9.3 2566 divided by 22 = 2(566 - 2) = 2564

Equation at the end of step 9 :

2564m292n294 m6n4

———————————— • ————

49 16

Step 10 :

Multiplying exponential expressions :

10.1 m292 multiplied by m6 = m(292 + 6) = m298

Multiplying exponential expressions :

10.2 n294 multiplied by n4 = n(294 + 4) = n298

Dividing exponents :

10.3 2564 divided by 24 = 2(564 - 4) = 2560

Final result :

2560m298n298

————————————

49


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