Question

Make M the subject (TRANSPOSITION)

Answer 1

Factor M on the right hand side:

$I = M\left(\dfrac{R^2}{4}+\dfrac{l^2}{12}\right)$

We can rewrite the parenthesis as

$I = M\left(\dfrac{3R^2}{12}+\dfrac{l^2}{12}\right) \iff I = M\left(\dfrac{3R^2+l^2}{12}\right)$

Now we can divide both sides by the parenthesis, and we have

$I = M\left(\dfrac{3R^2}{12}+\dfrac{l^2}{12}\right) \iff I = M\left(\dfrac{3R^2+l^2}{12}\right) \iff I\left(\dfrac{12}{3R^2+l^2}\right) = M \iff M=\dfrac{12I}{3R^2+l^2}$

Answer 2

Answer:

$M = \dfrac{12l}{3R^2+l^2}$

Step-by-step explanation:

$I = \dfrac{MR^2}{4}+\dfrac{Ml^2}{12}\Big|\cdot 12 \\ \\ 12l = 3MR^2+Ml^2 \\ \\ 12l = M(3R^2+l^2) \\ \\ M = \dfrac{12l}{3R^2+l^2}$