Question

HELP ME WITH THIS
1) |3p|=3p
2) |7y-3|=3-7y

Answer 1

do you know

if \(|a|=b \\ \implies a=b \quad or \quad a=-b\)
?

Answer 2

so if i have \(|a|=a\)
i will have ,
a=a or a=-a

a=-a will give me a= 0

same for the case of |a| =-a

then a=-a or a=a , so, a=0

Answer 3

yes

Answer 4

A method is to square both sides to remove the modulus.

(|3p|)^2 = (3p)^2

Another method is like what hartnn did;)

Answer 5

@Farheen28
are you getting these methods ?
ask doubts...

Answer 6

so the answer is 0 ?

Answer 7

for both, YES

Answer 8

i mean 3p=0 gives p=0
but
7y-3 =0
gives y= ... ?

Answer 9

3/7 right?

Answer 10

correct! :)

Answer 11

won't we solve it by separating the cases like
7y-3=3-7y and another would be -7y+3=3-7y ? @hartnn

Answer 12

we have to solve like that only
thats why i gave you example with "a"

-7y+3=3-7y is always true and will give you nothing
7y-3=3-7y will give you y=3/7 :)

Answer 13

oh i got it. but for the first one the answer in the book is p>=0, how is this?

Answer 14

thats because of the definition of |...|

|negative stuff| = +stuff
(absolute sign makes the quantity positive)

so, say if your p is negative, like -1
|-3| = -3
which is NOT TRUE , because |-3| actually = 3

hence there is a restriction on p that it must be positive or 0
hence p>=0

got it ?

Answer 15

yes :D thanks a ton

Answer 16

welcome ^_^