efectuati utilizind formulele calcului prescurtat:
a) (2-3a)(2+3a)
b) (4m+n)²


Răspuns :


[tex](2 - 3a)(2 + 3a) = {2}^{2} - (3 {a)}^{2} = 4 - 9 {a}^{2} [/tex]
[tex](4m + n {)}^{2} = (4m {)}^{2} + 2 \times 4m \times n + n {}^{2} = 16m {}^{2} + 8mn + n {}^{2} [/tex]



(2-3a) (2+3a)=4-9a²
(4m+n)²=16m²+8mn+n²