For now we do not know what u equals, but we do know that 20/5 = 4, because 20/5 simplified is just 4 since the fraction means 20 ÷ 4. Now that we are back to the question, with 2/5; if you multiply by 10 the numerator will then be 20. And now the equation is true! Hope this helps!
![\left[\begin{array}{ccc}\boxed{\boxed{ \frac{6}{4}}} \end{array}\right] = \left[\begin{array}{ccc}\boxed{\boxed{150}}\end{array}\right]](https://tex.z-dn.net/?f=%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%5Cboxed%7B%5Cboxed%7B%20%5Cfrac%7B6%7D%7B4%7D%7D%7D%20%5Cend%7Barray%7D%5Cright%5D%20%3D%20%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D%5Cboxed%7B%5Cboxed%7B150%7D%7D%5Cend%7Barray%7D%5Cright%5D%20)