=[3(x+5)]²-(x-7)²

=(3x+15+x-7)(3x+15-x+7)

=(4x+8)(2x+22)

=8(x+2)(x+11)

=20 nha ^-^

Ta có:

8x + 2x = 10 

=> x.(8 + 2) = 10

=> x . 10 = 10

=> x = 10 : 10

=> x = 1

nước Anh

a) 17,58 x 43 + 57 x 17,58

= 17,58 x ( 43 + 57 )

= 17,58 x 100

= 1758

b) 43,57x2,6 x[630-315x2]

= 43,57 x 2,6 x [ 630 - 630 ]

= 43,57 x 2,6 x 0

= 0

However, if the case of shyness is severe, when important occasions are missed or a person’s social, educational or professional life is affected, (25)_______ the label “shyness” is inappropriate. (26)______ this stage, it is termed “social phobia”. Those suffering (27)_______ this condition are very often bright, talented and sensitive people. But feelings of social isolation, resulting (28)_______ loneliness, can lead to additional problems (29)______ as alcohol abuse or addiction to medication. Fortunately, a number of treatments are available and come in the form of individual (30) ________ group therapy and training. Therefore, a person who has social phobia has an excellent chance of recovering.

Keeping away from such situations is not really a solution, of course, and if a shy person can manage to overcome their fears they (23)_______ gain a feeling of self-satisfaction as (24)________ as improving their social life.

Most people (20)_______ have this condition, suffer feelings of discomfort and anxiety at the (21)_________ of meeting others, especially at social gatherings (22)________ parties.