Which property must be true for the lines y=m1x+c1y = m_1x + c_1y=m1x+c1 and y=m2x+c2y = m_2x + c_2y=m2x+c2 to be the same line if c1≠c2c_1 \neq c_2c1=c2?
m1=m2m_1 = m_2m1=m2 and c1=c2c_1 = c_2c1=c2
m1⋅m2=−1m_1 \cdot m_2 = -1m1⋅m2=−1
They cannot be the same line
m1=m2m_1 = m_2m1=m2