Question

13. Find the value of using (a-b)²

formula (19)²

and (38)²



15. Use the formula (a+b)(a-b) = a² – b²

and find the value of

(i) 32 x 28 (ii) 51 x 49​

Answer 1

13. 19^2=(20-1)^2

=20^2+1^2-2X20X1

=400+1-40

=361

38^2=(40-2)^2

=40^2+2^2-2X40X2

=1600+4-160

=1444

15. 32X28=(30+2)(30-2)

=30^2-2^2

=900-4

=896

51X49=(50+1)(50-1)

=50^2-1^2

=2500-1

=2499

hope it helps!!!!

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