10(-1c+7)-3c
(-10c+70)-3c
-13c+70 is your answer
Perpendicular lines have slopes that multiply to -1
get into y=mx+b form
minus 15x both sides and divide by -5
y=3x-7/5
slope is 3
3 times what=-1?
what=-1/3
so the slope is -1/3
so
y=-1/3x+b
we use the point (0,-4)
x=0 and y=-4
-4=-1/3(0)+b
-4=b
y=(-1/3)x-4 is da equation
The best way to answer this would be making a graph
For 1 sign it costs 54.50 and he makes 15
For 2 signs it costs 59 and he makes 30
For 3 signs it costs 63.50 and he makes 45
For 4 signs it costs 68 and he makes 60
For 5 signs it costs 72.50 and he makes 75
This means that after 5 signs Larry will be making profit
(x^2)+4x-12=48
I Hope this is what you were looking for. If it isn't this just plug it in
x=6
