Question

[nguyen kieu quyen]

phan tich da thuc thanh nhan tu bang phuong phap dung hang dang thuc

1)tinh nhanh

a)7²  -27² =?

b)37² -13²=?

c)2002²-2²=?

giai giup minh nha

Answer 1

[Minh Triều]

a)7²  -27² =(7-27)(7+27)

=-20.34

=-680

b)37² -13²=(37-13)(37+13)=24.50

=1200

c)2002²-2²=(2002-2)(2002+2)

=2000.2004

=4008000