You have the following vertices of a triangle:
A(1,1)
B(4,1)
C(4,5)
For the translation four untis to the right, consider this kind of translation means that it is necessary to sum 4 units to the x-coordinate:
A(1,1) => A'(1+4,1) = A'(5,1)
B(4,1) => B'(8,1)
C(4,5) => C'(8,5)
Next, a translation three units up is done by adding 3 units to the y-coordinate of points A', B' and C':
A'(5,1) => A''(5,1+3) = A''(5,4)
B'(8,1) => B''(8,4)
C'(8,5) => C''(8,8)
Next, a reflection around y=-1 consists in subtracting to the y-coordinate units equivalent to the vertical distance to the line y =-1, just as follow:
for the point A''(5,4) you can notice that the vertical distance of the y-coordinate, which is 4, to the line y=-1 is 5 units, then, it is necessary to subtract 5 units to such line:
A''(5,4) => A'''(5,-1-5)=A'''(5,-6)
for the point B''(8,4), the distance is again 5 units, then, you have:
B''(8,4) => B'''(8,-1-5) = B'''(8,-6)
for the point C''(8,8) the distance from y-coordinate y=8 to the line y=-1 is 9 units, then, yu subtract 9 units to -1:
C''(8,8) => C'''(8,-1-9) = C'''(8,-10)
Hence, the final points are:
A'''(5,6)
B'''(8,-6)
C'''(8,-10)