Let P1 and P2 be the proportion of boys in each year.
In order to compare them we should pur the two proportions into simple forms.
P1 = (Number of boys) / (
In order to simplify this equation, first we need to expand the two brackets.
To expand 5a(4b - 3) we multiply 5a with each term inside the brackets.
a.) dy/dx+10x^4+20x^3
d^2y/dx^2=40x^3+60x^2
b.)sub in x=-1 to dy/dx=10(-1)^4+20(-1)^3
=-10
therefore, decreasing