Question 304477
On this line y =0.15x+ 0.79 is the representation of the average cost of gas each year.
 0.11x - y = -0.85 estimates the price of gas in January of each year.
convert this equation to the slope intercept form like the 1st equation
-y = -.11x -.85
get rid of all those negatives, multiply by -1
y = .11x + .85
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Do these lines expect to be intersecting, parallel, or perpendicular?
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Looking at the slopes: .15 for the 1st equation and .11 for the 2nd, we know
they are not parallel and will intersect at some point. (parallel lines have equal slopes).
:
Graphing these two equations will confirm this:
{{{ graph( 300, 200, -4, 6, -1, 2, .15x+.79, .11x+.85) }}} 
Intersect when x=1.5