<PRE><B>Question 829307</B>
Some thought should give you how to see this is a system of linear equations, two variables.


x=0 for time NOW.  Number of bugs is y, and number of months is x.


Ladybugs:  slope is 2 and y intercept is 15.  The equation is {{{y=2x+15}}}.


Aphids:  slope is {{{-3/1=-3}}}.   The y intercept is 175.  The equation is {{{y=-3x+175}}}.


WHEN do these two equations have the same point, or, what is the intersection point?
{{{highlight(2x+15=-3x+175)}}}
SOLVE FOR x.</PRE>