(x+5)(x-5)=
(a+√7)(a-√7)=
(25-b)(25+b)=
(√30-t)(√30+t)=


Răspuns :

x^2-25
a^2-7
625-b^2
30-t^2
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folosim regula calculului prescurat
(a+b)(a-b)=a²-b²

1) x²-5²=x²-25
2)a²-√7²=a²-7
3)25²-b²=625-b²
4)✓30²-t²=30-t²