we have that
4x²-25y²-8x+50y-121=0
Group terms that contain the same variable, and move the constant to the opposite side of the equation
(4x²-8x)+(-25y²+50y)=121
Factor the leading coefficient of each expression
4(x²-2x)-25(y²-2y)=121
Complete the square twice. Remember to balance the equation by adding the same constants to each side.
4(x²-2x+1)²-25(y²-2y+1)²=121+4-25
Rewrite as perfect squares
4(x-1)²-25(y-1)²=100
Divide both sides by the constant term to place the equation in standard form
(4/100)(x-1)²-(25/100)(y-1)²=100/100
(1/25)(x-1)²-(1/4)(y-1)²=1
[(x-1)²]/25-[(y-1)²]/4=1
the answer is
[(x-1)²]/25-[(y-1)²]/4=1