Mathematics: Post your doubts here!

[Haya Ahmed]

Guys can you solve Q9 and Q10 with explainations .. !! the answer of Q9 is 3 and Q10 is 2.2

 

[Thought blocker]

No pic!!

Guys can you solve Q9 and Q10 with explainations .. !! the answer of Q9 is 3 and Q10 is 2.2

 

[Haya Ahmed]

Thought blocker

 

[Rutzaba]

what am i supposed to do here?

 

[Thought blocker]

View attachment 47868

Thought blocker

what am i supposed to do here?

I cannot see pix, do help her.

 

[Haya Ahmed]

Thought blocker really ?! .. I posted the pic twice now!

 

[Thought blocker]

Thought blocker really ?! .. I posted the pic twice now!

I have a problem na!

 

[Thought blocker]

Share the link.

 

[Rutzaba]

Thought blocker really ?! .. I posted the pic twice now!

1/ root 28?

 

[Haya Ahmed]

1/ root 28?

nope .. the answer for Question 9 is 3! ... btw ignore Q10 I solved it and here is the picture again !

Thought blocker

 

[Rutzaba]

ph sorry
the undercube of 27

 

[Rutzaba]

nope .. the answer for Question 9 is 3! ... btw ignore Q10 I solved it and here is the picture again !

Thought blocker

yes yes im sorry thats the correct ans wait lemme tell u how

 

[Thought blocker]

nope .. the answer for Question 9 is 3! ... btw ignore Q10 I solved it and here is the picture again !

Thought blocker

Found
Properties to be used here :

lnx + lny = ln(xy)
lnx - lny = ln(x/y)
3lny = ln(y^3)

Then
lnx + 3lny - ln2 = ln(xy^3/2)
and
lnx^4 - ln54 = ln(x^4/54)

Then
ln(xy^3/2) = ln(x^4/54)
xy^3/2 = x^4/54
y^3 = 2x^4/54x
y^3 = x^3/27
x^3 = 27y^3
x = 3y
x/y = 3

Hope it helps

 

[Rutzaba]

ln x +3lny (in the next step we will keep the power of y 3 it is log property) -ln2= ln x^4 -ln54
lnx +ln y^3-ln2 =lnx^4 -ln54
now from log we know + is multiply and minus is divide
so ln[( x.y^3)/2]= ln (x^4 /54)

 

[shaminou]

Guys can you solve Q9 and Q10 with explainations .. !! the answer of Q9 is 3 and Q10 is 2.2

ln X+ lnY ^3 -ln2=ln X^4-ln 54
ln X -ln X^4 +ln Y^3= -ln 54 +ln2
ln(X.Y^3/X^4)= ln(2/54)
remove ln:
Y^3/X^3= 1/27
Y^3=1
Y=1
X^3=27
X=3
X/Y=3/1=3

 

[Rutzaba]

haha

 

[Thought blocker]

haha

What?

 

[Rutzaba]

What?

so many people to come up with a solution

 

[Thought blocker]

so many people to come up with a solution

'Coz that was easiest.

 

[Haya Ahmed]

Thanks Guys !! .. btw are you all in Gr 12 ??