To factor an expression, first you have to find the GCF or Greatest Common Factor of all of the pieces of the expression.
The GCF of 2y^2 and -4y is 2y
So, to factor this expression, we need to divide all of the pieces of the expression by the GCF.
2y(y-2)
2y^2 - 4y in completely factored form is 2y(y-2)
Hello, please consider the following.
a) You need to replace x by -1.

b) You need to replace x by 2t and simplify.

c) You need to replace x by t-2 and develop, and simplify.

Thank you.
The construction that you can use to prove the Pythagorean
Theorem based on similarity of triangles is 2nd construction. Please see the
attached file.
To add, in mathematics, the Pythagorean theorem, also
known as Pythagoras's theorem, is a fundamental relation in Euclidean
geometry among the three sides of a right triangle. It mentions that the sum of
the squares of the other two sides is equal to the square of the hypotenuse
(the side opposite the right angle).