y'=-1-4x+4y,
Euler’s Method: y₁=y₀+hy'(x₀,y₀) where (x₀,y₀)=(1,y(1))=(1,-1) and h=0.5 (step value).
y₁=-1+0.5(-1-4-4)=-1-4.5=-5.5.
x₁=1+0.5=1.5, therefore y(1.5)=-5.5.
y₂=y₁+hy'(x₁,y₁)=
-5.5+0.5(-1-6-22)=
-5.5-14.5=-20.
x₂=1.5+0.5=2, therefore y(2)=-20.