What is the solution to 4x2-20x equals 25 equals 0?

Answer 1

4x^2-20x-25=0 is the same problem of course.

You cannot factor this so you can solve with the quadratic formula or

completing the square. Of course you could also use a calculator or computer

algebra system.

Let's complete the square.

4x^2-20x=25

4(x^2-5x)=25

x^2-5x=25/4

(x-5/2)^2=25/4+25/4

(x-5/2)^2=25/2

x-5/2=+ or - 5/square root (2)

x=5/2+5/sqrt(2)

or x=5/2-5/(sqrt2)

We can rationalize the denominator

5/2+5(sqrt(2)/2

5/2-5(sqtrt(2)/2

or

(5+5(sqrt2))/2

or (5-5(sqrt(2))/2

also written as

5(1+sqrt(2))/2

5(1-sqrt(2))/2