6) \( \left(2 \mathrm{X}^{3}-5\right)\left(\mathrm{X}^{2}+1\right)= \)

Jika \( \left(\begin{array}{cc}-2 & 2 \\ 5 & y\end{array}\right)\left(\begin{array}{ll}5 & 3 \\ x & 4\end{array}\right)=\left(\begin{array}{cc}-6 & 2 \\ 27 & 19\end{array}\right) \), cari nilai \( x \) dan \( y \). If \( \left(\begin{array}{cc}-2 & 2 \\ 5 & y\end{array}\right)\left(\begin{array}{cc}5 & 3 \\ x & 4\end{array}\right)=\left(\begin{array}{cc}-6 & 2 \\ 27 & 19\end{array}\right) \), find the value of \( x \) and \( y \)

c) \( \sqrt{2 x}-1=\sqrt{x+1} \)

\( f(x)=(2 x+3)^{2}-12 x \) odd or eveh?

What values of \( a \) satisfy the equation \( (a - 5)(a + 1) = 0 \)?

d) \( \left[\frac{\left(\frac{x+y}{x-y}\right)^{2}-\left(\frac{x-y}{x+y}\right)^{2}}{\left(\frac{x+y}{x-y}\right)^{2}+\left(\frac{x-y}{x+y}\right)^{2}-2}\right]:\left(1+\left(\frac{x}{y}\right)^{2}\right) \)