Answer:

Explanation:
A second-degree equation is often expressed as:

where a,b, and c are constants.
Solving with the quadratic formula:

The equation to solve is:

We need to express the equation as mentioned above. The right side of the equation must be zero, so we subtract 1:

Now we have the values to solve the equation:
a=1, b=-4, c=-1
Applying the formula:



Since 20=4*5:

Taking the square root of 4:

Simplifying by 2:

Two solutions are found:
