Question

Dau COROANA celui mai corect raspuns

Answer 1

A) x+3=9

x=9-3

x=6

Ridical din 6 +3=3

3=3

x =6

Answer 2

Răspuns:

a) $\sqrt{x+3} =3$  /²

x+3=9   x=6

b) $\sqrt{7x-5} -x+1$   /²

7x-5=x²+2x+1

x²-5x+6=0

x(x-2)-3(x-2)=0

(x-2)(x-3)=0   x={2; 3}

c) $\sqrt{x-1} +\sqrt{x+3} =2$   /²

x-1+2$\sqrt{(x-1)(x+3)}$+x+3=4  

2x+2$\sqrt{x²+2x-3}$=2    /:2

$\sqrt{x²+2x-3}$=1-x  /²

x²+2x-3=1-2x+x²

4x=4    x=1

Explicație pas cu pas: