Question

please give me answers of all questions fast. ​

Answer 1

Answer:

1. the numbers which has unit digit 0,2,3,5,7 cut them all the remaining numbers are perfect square

2. a.. 69^2

we can write this as (70-1)^2

by using identity (x-y)^2= x^2 -2xy+y^2

we get, (70-1)^2= 70^2-(2×70×1)+ (-1)^2

=4900-140+1

= 4761

REST OF THE PARTS ARE DOING BY SAME METHOD.

BUT IF THEY ARE NOT BREAK IN MINUS AS

IF IT COMES 61^2=(60+1)^2

THEN ONLY THE IDENTITY .....

(X+Y)^2=X^2+(2×XY)+Y^2

3. firstly you have to find sqrt. of the number

then, whatever the answer will come write its unit digit (at once place).

4.(a) firstly find square of 15 and then of 16

subtract the square of 15 from 16

REST OF PARTS ARE DONE BY SAME METHOD

5. Take any perfect number and devide it by 3 and 4 separately.

your answer will come

HOPE THESE ANS WER SATISFY YOU.