Line \(l_1\) represents the graph of \(3x + 4y = -14\). Line \(l_2\) passes through the point \((-5,7)\), and is perpendicular to line \(l_1\). If line \(l_2\) represents the graph of \(y=mx +b\), then find \(m+b\).
+1223 first line: 3x + 4y = -14
4y = -3x - 14
y = -3x/4 - 7/2
second line: parallel to first line, so the slope is 4/3. this line also passes through (-5, 7) so we can write this line in point slope form first:
y - 7 = 4/3(x + 5)
y - 7 = 4x/3 + 20/3
y = 4x/3 + 41/3
m + b = 4/3 + 41/3 = 15
