Question

Find dy/dx
y=(116-21x^2)/120

Hi! I dont understand what to do here, please help!

Answer 1

\[y=\frac{ 116-21x^2 }{ 120 }\]


here is the equation again

Answer 2

\[y=\frac{116}{120}-\frac{21}{120}x^2\]
therefore:
\[y'=-\frac{21*2}{120}x^{2-1}\]\[=-\frac{21}{60}x\]

Answer 3

\[y= \frac{ 116 }{ 120 }-\frac{ 21x^{2} }{ 120 }\]

Answer 4

now find dy/dx

Answer 5

the \[\frac{ 116 }{ 120 } \] goes to zero when applying the power rule (I think thats what its called) right? and then the next part goes to \[\frac{ -21 }{ 60 }x\] but the answer in my text book says its -7x/20, so you divide both sides by three to get that

Answer 6

-21x/60 (cancellation with 3 )
=-7x/20

Answer 7

u r right

Answer 8

Ok great! Thanks! :D

Answer 9

u r welcome:)