$\sqrt[]{4x-2}$ . $\sqrt[]{4x-1}$ + $\sqrt[]{4x+2}$ . $\sqrt[]{4x-1}$
= $\sqrt[]{4x-1}$ . ($\sqrt[]{4x-2}$ +$\sqrt[]{4x+2}$ )
= [ $\sqrt[]{4x-1}$ . ($\sqrt[]{4x-2}$ +$\sqrt[]{4x+2}$ ) ]²
= $(4x-1)(4x+2+4x-2+2$$\sqrt[]{(4x-2)(4x+2)}$ )
= (4x-1)(8x+ 2$\sqrt[]{8x²-4}$
= (4x-1)(8x+ 2$\sqrt[]{4(2x²-1)}$
= (4x-1)(8x+ 4$\sqrt[]{2x²-1}$
= (4x-1)(8x+ 4$\sqrt[]{2x²-1}$