40 points
prove the polynomial identity (3x + 1) ^ 2 - 2(3x + 1) = (3x + 1)(3x - 1) drag and drop the expressions to correctly complete the proof of the polynomial identity.

expression #3 is not equivalent. the others are.

step-by-step explanation:

this can be solved first with pythagorean theorem, which tells us to square both legs of the triangle and sum it. this will be equal to the square of the hypotenuse.

the hypotenuse is the side "opposite" the 90 degree angle, which is x.

so we can write using pythagorean theorem,

simplifying:

to further simplify this radical, we need to use the property  

thus