Question

plzz find the two answer​

Answer 1

Use the formula (a+b)(a-b) = a²-b² ----- (I)

Given that, 20.5 × 19.5

i.e., (20 + 0.5)(20 - 0.5) ( Rearranging the numbers)

i.e., 20² - 0.5² ( using (i) )

i.e., 400 - 0.25

i.e., 399.75 is your answer

hope it helps

Answer 2

Answer:

20.5

(20+0.5)

(a+b)=a^2+b^2+2ab

(20)^2+(0.5)^2+2×20×0.5

40+0.25+20

60.2