Which of the following is an example of the difference of two squares? x2−9x2−9 (x−9)2 x3−9x3−9 (x+9)2

 x²−9

Step-by-step explanation:

A square number is obtained ehen we multiply a number to itself.

For example: 5 × 5 = 5² = 25 [It is a square number]

We can do this in expression too, For example: z×z =z²

From all the given options, only x²−9 has both terms as square.

∵ x² = x × x

and 9 = 3×3= 3²

So that,  x²−9  =(x)²-(3)²

Hence, the correct option is x²−9.

d. bc = 12 and ef = 16

step-by-step explanation:

we are given that δabc : δdef such that .

also, it is given that

so, from the options, we need that .

a.

b.

c.  

d.

as, we can see that only option d gives the same ratio as i.e. .

hence, the possible lengths are bc = 12 and ef = 16.

#15. square

step-by-step explanation:

because quadrilatural (idk how to spell it) means somthing that is not 3d or like, equal sides (or somthing like that   you know what i meanz)

hope this halps!

bai!