I is called the subject of the formula.In the formula
I is called the subject of the formula.
To make 'P' the subject of the formula:
P x T x R = 100 x I
If
make 'a' the subject of the formula.
m(a + b) = a Cross multiplying.
am + bm = aam -a = - bm Take terms containing 'a' to one side.
a(m - 1) = -bm remove 'a' as a common factor.


make 'y' the subject of the formula.

Squaring both sides
ma2 = xy
i.e.,

(i) Make b the subject of the formula.
(ii) If a = 9 and R = 3, find b.

(Invertendo)
(ii) 
