1. Write down the equations:
L1: 2x - 2y + 1 = 0
L2: 2x + 2y + 3 = 0
2. Calculate the slope for L1:
m_1 = -\frac{2}{-2} = 1
3. Calculate the slope for L2:
m_2 = -\frac{2}{2} = -1
4. Compare the slopes. Since m_1 and m_2 are negations:
L1\ and\ L2\ are\ perpendicular.