For this case we have that by definition, the point-slope equation of a line is given by:

Where:
m: It's the slope
It is a point through which the line passes
According to the statement data we have:

Substituting we have:

By law of signs of multiplication we have to:

Answer:
The requested equation is: 
We are told that 21% of the total cans is 63 cans, therefore
100% of all the cans collected would be.
(63*100)/21=300 cans were collected in all
Um sounds nice i guess its kind of funny simplify hairy fractions
90% of <span>£41 = 90/100 × 41 = </span><span>£36.9
</span>£41 decreased by 90% = 41 - 36.9 = <span>£4.1</span>