TRANSPOSITION OF FORMULAE B4

If Q = c(d + m)    make a the subject of the formula.

             (d – m)

Solution

Q = c(d + m)   

         (d – m)

(d – m) x Q = c(d + m) x (d – m)   multiply by(d - m) on both sides.

                         (d – m)

(d – m) x Q = c(d + m) open the brackets on both sides.

Qd – Qm = cd + cm

Qd – cd = Qm + cm (collect the terms containing m together)

Qd – cd = m(Q + c)

Qd – cd = m(Q + c) ¹               Divide by (M + t) on both sides.

(Q + c)         (Q + c) ₁

Qd – cd = m

(Q + c)        

Hence  m =   Qd – cd

                       (Q + c)