Răspuns :
a) (5-3)²=5²+(-3)²+2·5·(-3)
5²-2·5·3+3²=25+9+10·(-3)
25-30+9=25+9-30
-5+9=34-30
4=4
b) (-7+2)²=(-7)²+(+2)²+2·(-7)·(+2)
(-7)²+2·(-7)·2+2²=49+4-14·2
49-28+4=49+4-28
21+4=53-28
25=25
a) (5-3)²=5²+(-3)²+2·5·(-3)
5²-2·5·3+3²=25+9+10·(-3)
25-30+9=25+9-30
-5+9=34-30
4=4
b) (-7+2)²=(-7)²+(+2)²+2·(-7)·(+2)
(-7)²+2·(-7)·2+2²=49+4-14·2
49-28+4=49+4-28
21+4=53-28
25=25