Question

3) DACA a+b=3 si a-b=7, calculati:
a) a^2 - b^2
b) a^2+ 2ab+ b^2

Answer 1

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Answer 2

{a+b=3
{a-b=7 la aduni
2a \ =10
a=5        5+b=3   b=-2
a) 5^2-(-2^2)=25-4=21
b)5^2+2x5x-2+(-2^2)=10-20+4=-6