Question

An inequality is shown below:

-np - 5 ≤ 4(c - 2)

Which of the following solves for n?
@amistre64 @ganeshie8 @satellite73 @SolomonZelman

Answer 1

do we assume n is postive to start with?

Answer 2

n ≥ - the quantity 4 times c minus 3 all over p
n ≥ - the quantity 4 times c minus 13 all over p
n ≤ - the quantity 4 times c minus 3 all over p
n ≤ - the quantity 4 times c minus 13 all over p

Answer 3

if we have -a < b, and want to solve for a, its best to add it over

0 < b + a, therefore: -b < a this avoids alot of headache trying to remember to flip signs

Answer 4

@amistre64 but my problem is much more complex

Answer 5

@perl

Answer 6

yes

Answer 7

-np - 5<=4(c - 2)
-np - 5 <= 4c - 8
-np <= 4c -8 + 5
-np <= 4c - 3
did you get up to here?

Answer 8

ok if you divide by a negative, you have to change the sign of the inequality

Answer 9

so n<=4c-3/p

Answer 10

-np <= 4c-3

n >= - (4c - 3 ) / p

Answer 11

you just need the minus in front

Answer 12

so the answer is A

Answer 13

sorry i can't give the answer :)

Answer 14

is p assumed to be positive to start with?

Answer 15

lets see if it matter:

-n(-3) > 20

n < 20/-(-3)

n < 20/3 < 6 1/3

so, let n=-1 since -1 < 6

-(-1)(-3) > 20 is this true or false?

Answer 16

true

Answer 17

you think -3 is bigger than 20?

Answer 18

oh wait no i had my sign messed up

Answer 19

when we divide by a variable, we have to have some sort of restrictions on it in an inequality; since a negative value flips the equailty sign

Answer 20

okay

Answer 21

the answer is eaither a or b because thats the ones that the sign flips

Answer 22

-np - 5 <= 4(c - 2)

-4(c-2) - 5 <= np
-------------------

if p is positive then

[-4(c-2) - 5]/p <= n
-------------------

if p is negative then

[-4(c-2) - 5]/p >= n

Answer 23

okay

Answer 24

i spose its generally assumed the p is positive tho

Answer 25

so its A