Question

Which shows 60^2 − 40^2 being evaluated using the difference of squares method?

(A)60^2-40^2=(3600+1600)(3600-1600)=10,400,000
(B)6^2-40^2=3600-1600=2,000
(C)60^2-40^2=(60-40)^2=20^2=400
(D)60^2-40^2=(60+40)(60-40)=(100)(20)=2,000

Answer 1

D. The answer has to be 2,000, eliminating A and C. B doesn't even use the original equation, as well as incorrectly solving the method, so D is the correct answer, even if you don't understand the principles.

Answer 2

Option D -
`60^2-40^2=(60+40)(60-40)=(100)(20)=2000`

Explanation:

Given : Expression
`60^2-40^2`

To find : Which shows expression being evaluated using the difference of squares method?

Solution :

The best method to find the difference of squares method is by using identity,

`a^2-b^2=(a+b)(a-b)`

According to question,

a=60 and b=40

`60^2-40^2=(60+40)(60-40)`

`60^2-40^2=(100)(20)`

`60^2-40^2=2000`

Therefore, Option D is correct.