Tìm x biếta) $\sqrt{x + 1}$ + $\sqrt{9x + 9}$ = 4
b) $\sqrt{x - 2}$ - $\sqrt{x^{2} - 2x}$ = 0
c) $\sqrt{5x}$ - $\sqrt{3x}$ = 2
d) $\sqrt{3x - 1}$ = $\sqrt{\sqrt{3}}$
e) ( 6 - 2$\sqrt{5}$ ) $\times$ $x^{}$ = $\sqrt{5}$ - 1
f) $b^{2}$$x^{2}$ - $b^{2}$ = $x^{2}$ ( b > 1 )
g) a$x^{}$ + 3 = $\sqrt{3}$ $\times$ $x^{}$ + $a^{2}$ (a khác $\sqrt{3}$)
h) $\sqrt{4x - 20}$ + $\sqrt{x - 5}$ - $\frac{1}{3}$ $\times$ $\sqrt{9x - 45}$ = 4