Melody

$$\frac{-50bd}{20}=\frac{-5bd}{2}$$

If you wanted to this could also be written as -2.5bd

and

sin(150)=sin(30)

I would have said

cos(300)=cos(360-300)=cos(60)=sin(30)

Yes what do you want to do ?

Maybe this will help

Thanks Radix,

It did not occur to me that it was money :/

Look at Holly's ONLY shirt and shoes!!

She is not greedy!  

She is Needy   

$$\frac{-11}{4}\div 14=\frac{-11}{4}\times \frac{1}{14}=\frac{-11}{56}$$

Good thinking Chris  

More practice

Part B

11A+8B=94

Largest common factor of 11 and 8 is 1.  One is a factor of 94.  So this does have integral solution.

2 elevens and 9 eights confusions is the only solution.  

Thanks Chris and anon - I think we might need change too :((

Mellie this isn't really for you - I am just practicing doing diophantine equations  :))

Part C

8A+11B=69

The FCF of 8 and 11 is 1    and 1 goes into 69 so this does have integral solutions  :/

8*-276+11*207=69

8A+11B=69

So 

A=-276+11N          B=207-8N

276/11=25 and a bit

A=-276+11*26=10         B=207-8*26=-1

Mmm       There are not any solutions!

Thanks Chris - I am going to put my 2c worth in now  

$$\\\frac{9}{44} + \frac{17}{36} \\\\
=\frac{9}{11*4} + \frac{17}{9*4} \\\\
=\frac{9*9}{11*4*9} + \frac{17*11}{9*4*11} \\\\
=\frac{9*9+17*11}{11*4*9} \\\\
=\frac{81+187}{11*4*9} \\\\
=\frac{268}{11*4*9} \\\\
=\frac{268\div 4}{11*4*9\div 4} \\\\
=\frac{67}{11*9} \\\\
=\frac{67}{99} \\\\$$