MaxWong

log is the logarithm.

if log x = y then 10^y=x

$\color{aqua}\sqrt{20}=2\sqrt{5}$

3 pence. It's impossible to make 3 pence with 4 and 5 pence stamps.

.......

Do you mean 5w+3w=64?

5w+3w=64

8w=64

w=8

x-y=2 ----(1)

x+y=8 ---- (2)

(1)+(2): 2x=10

x=5----- (3)

Subst. (3) into (1)

5-y=2

y=3

Therefore x=5 and y=3

What if the coin stood on the edge without falling to become a head or a tail?

I count that as a possible outcome.

$\color{red}(3x+4)(x-1)$

= $\color{orange}3x(x-1)+4(x-1)$<--- Multiplication Distributive Law

=$\color{lime}(3x)(x)-(3x)(1)+4x-4$ <--- Multiplication Distributive Law again

= $\color{blue}3x^2-3x+4x-4$<--- Multiplying out the brackets.

= $\color{purple}3x^2+x-4$<--- Combining like terms. Finish.

$\color{red}3h^2=512$

$\color{orange}h^2=\frac{512}{3}$

$\color{lime}h^2+0h-\frac{512}{3}=0$

Using quad. formula

$\color{blue}h_1=13.063945294843617$

$\color{purple}h_2=-13.063945294843617$

What is the percentage of maths book to all the textbooks in the library. This is one vital clue not given!

From Wikipedia, calculus is the study of changes.

You will calculate differentials and integrals in calculus. You will see things like

$\frac{d}{dx}x^2=2x$

$\int_{0}^{\pi}sinxdx= 2$<--- seemed like I was wrong :P

$\int{2x^2}=\frac{2x^3}{3}$