\(\displaystyle m^{2}-3m+2=0\)
\(\displaystyle m=2, \;\ m=1\)
\(\displaystyle Ce^{2x}+De^{x}\)
Using the initial conditions:
\(\displaystyle Ce^{2(0)}+De^{0}=2\)
\(\displaystyle 2Ce^{2(0)}+De^{0}=0\)
This gives two equations with two unknowns:
\(\displaystyle C+D=2, \;\ 2C+D=0\)
Solve for C and D.
This gives \(\displaystyle y=-2e^{2x}+4e^{x}\)