Question

When x<0, then \[\sqrt{x ^{2}+\frac{ 9x ^{2} }{ 16 }}\]
Is equal to:
\[A \frac{ 7x }{ 4}\]\[B -\frac{ 7x }{ 4 }\]
\[C \frac{ 5x }{ 4 }\]
\[D - \frac{ 5x }{ 4 }\]
\[E \frac{ 3|x| }{ 4 }\]
I know it must be simple,but olease can anyone give me any hints?

Answer 1

hey @bibby

Answer 2

@mathslover

Answer 3

First take lcm and then Convert numerator as a whole square....

Answer 4

sorry,but what is lcm?

Answer 5

LCM - Lowest Common Multiple.

Answer 6

so:
\[\sqrt{\frac{ 16x ^{2}+9x ^{2}}{ 16 }}=\sqrt{\frac{ 25x ^{2} }{ 16 }}\]
Like this?

Answer 7

and then just take out the square root? \[\frac{ 5x }{ 4}\]

Answer 8

or \[-\frac{ 5x }{ 4 }\]

Answer 9

oh it cant be negative when you take the square root?

Answer 10

it has to be negative as it is given that x is less than 0...

Answer 11

oh,I forgot,thanks a lot,vedic:}}}

Answer 12

when we take square root we get both roots for example sqrt of 4 gives 2 or (-2)...

Answer 13

u r welcome...:)