Question

What value of m will make 4x-7y=5 and 9x+my=3 parallel?

Answer 1

`l:y=m_1x+b_1\ and\ k:y=m_2x+b_2\\\\l\ ||\ k\iff m_1=m_2\\------------------------\\l:4x-7y=5\to-7y=-4x+5\to y=(4)/(7)x-(5)/(7)\\\\k:9x+my=3\to my=-9x+3\to y=-(9)/(m)x+(3)/(m)\\\\l\ ||\ k\iff-(9)/(m)=(4)/(7)\\\\cross\ multiply:\\\\4m=-9\cdot7\\\\4m=-63\ \ \ \ /:4\\\\m=-15.75\leftarrow answer`