Question

Aratati ca 9-(x+2)²=(1-x)(x+5), pentru orice x apartine R. dau coroana..... va rog​

Answer 1

Stim ca: a²-b²=(a-b)(a+b)

9-(x+2)²=(1-x)(x+5)

3²-(x+2) ²=(3-x-2)(3+x+2)=(1-x)(x+5)

9-(x+2)²=(1-x)(x+5)  pentru orice x∈R