a) (5x + 1)² = 36/49
⇔ \(\left[ \begin{array}{l}5x-1=6/7\\5x-1=-6/7\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}5x=13/7\\5x=-1/7\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=13/35\\x=-1/35\end{array} \right.\)
b) (x - 2/9)³ = (2/3)^6
⇔ x - 2/9 = (2/3)²
⇔ \(\left[ \begin{array}{l}x-2/9=2/3\\x-2/9=-2/3\end{array} \right.\)
⇔ \(\left[ \begin{array}{l}x=8/9\\x=-4/9\end{array} \right.\)
c) $(8x-1)^{2x+1}$ = $5^{2x+1}$
⇒ 8x - 1 = 5
⇔ 8x = 6
⇔ x = 3/4
d) (x-3,5)² + (y - 1/10)^4 ≤0
Vì (x-3,5)² ≥ 0 và (y-1/10)^4 ≥ 0
⇒ (x-3,5)² + (y - 1/10)^4 =0
⇒ $\left \{ {{(x-3,5)^2=0} \atop {(y-1/10)^4=0}} \right.$
⇔ $\left \{ {{x-3,5=0} \atop {y-1/10=0}} \right.$
⇔ $\left \{ {{x=3,5} \atop {y=1/10}} \right.$
