Melody

I like Chris's sugestion best.  "Overall" is meaningless.   It is worse than meaningless.  It is confusing.

And I still do not think that the first sentence makes sense.  

$$\begin{array}{rlll}
6(-1-y)&=&19\\\\
6(-1-y)&=&19\qquad &$next Divide both sides by 6$\\\\
-1-y&=&\frac{19}{6}\qquad &$next add 1 to both sides$\\\\
-y&=&\frac{19}{6}+1\\\\
-y&=&\frac{25}{6}\qquad &$next mult both sides by -1 $\\\\
y&=&\frac{-25}{6}\\\\
y&=&-4\frac{1}{6}\\

\end{array}$$

Happy I am impressed by how well you use the site calc but students need to learn how to do these by hand.

Why don't you learn how to do them by hand and then you can teach others.

$$\\p(x) = (7x^3+24x^2+25x+1)\quad -\quad (x^5+3x^3+9x)\\
p(x) = 7x^3+24x^2+25x+1\quad -x^5-3x^3-9x\\
p(x) = -x^5+7x^3-3x^3+24x^2+25x-9x+1\quad \\
p(x) = -x^5+4x^3+24x^2+16x+1\quad \\$$

Great answer  sasflower   

I do it a little differently.

10% of 20       now 10%=10/100    and   of is multiply *

so this becomes

10/100 * 20 = 1/10*20 = 2

You can use either.

It is like saying do I measure distance in miles or in kilometre.  You can use either.

The one that is required depends on the question.  

just press [2nd] then [asec]

just do it on the site calc

55sin168+2tan7/5/cos45

55*sin168+2*tan(7/5)/cos(45)

The first one doesn't make much sense to me 

$$\\sec^{-1}(5.9963)\\
=cos^{-1}(1/5.9963)\\$$

now you can just enter it into the  sit calc as 

acos(1/5.993)=

and you will get your answer

Make sure the calc is set to degrees (or radians if that is your preference) there is a button on the bottom left for this.

ALSO

acos stands for arc cos which is the same as inverse cos.