Question

Find (40² - 39²) + (38² - 37²) + (36² - 35²) + .... +(2² - 1²)

Answer 1

Answer:

Step-by-step explanation:

Let us see the first expression...

(40^2-39^2)=(40+39)(40-39)[using a^2-b^2 formula]

Therefore the answer of first expression is 40+39.

So,the answer of the above question will be----

1+2+3+4.....+39+40

So the answer is (40×41)÷2

=820

Hope it helps

Answer 2

So the answer is (40×41)÷2

=820