Question

radical din 4+x + radical din 4-× egal cu 8

Answer 1

(√4+X)+(√4-x)=8

ridicam la puterea a doua ambele parti ale egalitatii

(√4+x)²+(√4-x)²=64

aplicam formula (a+b)²=a²+2ab+b² si (a-b)²=a²-2ab+b²

4+2x√4+x²+4-2x√4+x²=64

8+2x²=64

2x²=56

x²=28

x=√28