Answer
$\dfrac{10i}{1-2i}=-4+2i$
Work Step by Step
$\dfrac{10i}{1-2i}$
Multiply the fraction by $\dfrac{1+2i}{1+2i}$:
$\Big(\dfrac{10i}{1-2i}\Big)\Big(\dfrac{1+2i}{1+2i}\Big)=\dfrac{10i+20i^{2}}{1-(2i)^{2}}=\dfrac{10i+20i^{2}}{1-4i^{2}}=...$
Substitute $i^{2}$ with $-1$:
$...=\dfrac{10i+20(-1)}{1-4(-1)}=\dfrac{10i-20}{5}=-4+2i$
