Răspuns:
a) [tex]\sqrt{x+3} =3[/tex] /²
x+3=9 x=6
b) [tex]\sqrt{7x-5} -x+1[/tex] /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) [tex]\sqrt{x-1} +\sqrt{x+3} =2[/tex] /²
x-1+2[tex]\sqrt{(x-1)(x+3)}[/tex]+x+3=4
2x+2[tex]\sqrt{x²+2x-3}[/tex]=2 /:2
[tex]\sqrt{x²+2x-3}[/tex]=1-x /²
x²+2x-3=1-2x+x²
4x=4 x=1
Explicație pas cu pas:
