Melody

3.1 - - 2.3 = 3.1+2.3 = 5.4

just like anon said :)

Top row of the calculator

$$\\\frac{(a+b)}{2}^2 - \frac{(a-b)}{2}^2\\\\
=\frac{(a^2+b^2+2ab)}{4} - \frac{(a^2+b^2-2ab)}{4}\\\\
=\frac{(a^2+b^2+2ab)-(a^2+b^2-2ab)}{4} \\\\
=\frac{a^2+b^2+2ab -a^2-b^2+2ab}{4} \\\\
=\frac{2ab +2ab}{4} \\\\
=\frac{4ab}{4} \\\\
=ab$$

$$\\(-1)^7
=-1*-1*-1*-1*-1*-1*-1\\
=(-1*-1)*(-1*-1)*(-1*-1)*-1\\
=1*1*1*-1\\
=-1$$

$$\\(-1)^{odd\; number}=-1\\
(-1)^{even\; number}=+1\\$$

A = 1/2    * base * height

y=-3-3=-6     (3,-6)

All too much for me MG        

it cannot be factored

Deg stands for degrees.  I expect you know what they are.

rad stands for radians.  Radians are also used to measure angles. 

there are  90 degrees in a right angle              there are    $$\frac{\pi}{2}$$  radians in a right angle

there are 180 degrees in a straight angle         there are $$\pi$$  radians in a straight angle

and

360degrees in a revolution.                           there are $$2\pi$$  radians in a revolutions

I didn't know how to do this so I gave myself a quick lesson from here

Watch th video and work through the video example

then put it together with your knowledge of how elimination method to solve simultaneous equations works.

$$\begin{pmatrix}
2 &1&0&|-4 \\
0 &-2&4&|+0 \\
3 &0&-2&|-11 \\
\end{pmatrix}$$

First you need to get rid of the 3 in the bottom left corner.

1)  multiply R1 by3  and R3 by 2     WRITE down the new matrix

2)  R1-R3  replaces R3                    WRITE down the new matrix  (the 3 has been replaced with a 0)

NOW there is a 3 in R3, C2  You have to get rid of it

3) mult R2 by 3 and mult R3 by 2    WRITE down the new matrix

4) R2+R3 replaces R3                    WRITE down the new matrix  (the 6 has been replaced with a 0)

NOW the diagonal must only contain ones

5) Multiply R1 by 1/6,      Multiply R2 by -1/6         and multiply R3 by 20

And you should be able to take it from there

answer

x=-3,    y=2,   and    z=1