Melody

Because he gets to serve a a lot.

I would have thought he'd had enough of that in his day job!   

5(3(2+5)-5)

Ok

First add what's inside the parentheses. 

2+5=7  CORRECT

Now use the order of operations to find the answer.

Multiplcation

Division

Addition 

Subtraction

so, you multiply first.

3*7=21        CORRECT

now subtract 5 from 21

21-5=16    CORRECT

Multiply 16 by 5 and you get the answer.

16*5=80        CORRECT

So, $${\mathtt{80}}$$ Is the answer.

CORRECT  CORRECT  CORRECT  CORRECT

EXCELLENT DRAGON      

If you want to put it in gradient and y intercept form then start by multiplying both sides by ab

You cannot solve.  There are too many variables.

Hey Dragon,

Why don't you give it a go and i will tell you if you are correct?

This is a straight forward question.

You just need to know that if a number is followed immediately by a bracket, there is an invisable x sign between them.  

$$\frac{2\sqrt{5}}{\sqrt3-\sqrt7}}\times \frac{\sqrt3+\sqrt7}{\sqrt3+\sqrt7}}$$

That will give you a rational denominator.

add 2.5 to both sides and then multiply both sides by 4

A model of a car has a scale of 1:25. The model is 18 cm long. Calculate, in metres, the actual length of the car

The real one is 25 times bigger.   

Greek letters are usually used for angles.  (That is beta)