Question

descompuneti in factori x la a doua -81

Answer 1

x²-81=(x+9)(x-9) Verificare:(x+9)(x-9)=x²-9²=x²-81

Formula utilizata: a²-b²=(a+b)(a-b) $\text{,,Formula diferentelor de patrate''}$

Mult noroc!  

Answer 2

(x²-81)=(x²-9²)=(x+9)(x-9)