When we dilate the figure by a scale factor k, in this case, k=10:
"the algebraic representation of the dilation is (x, y) → (kx, ky)."
So the point A(0,2) after multiplying the x and y coordinate by 10:
A(0,2) = A'(10*0,10*2) = A'=(0,20)
Now with the others points:
B(3,-2) = B'(10*3,10*-2) = B'(30,-20)
C(-1,-4) = C'=(10*-1.10*-4) =B'=(-10,-40)