<span>(18<span>t<span><span>^2</span><span> </span></span></span>+ 9<span>t^<span><span>2</span><span></span></span></span>) + (−7t −3t) + 20
</span><span><span>27<span>t<span><span>^2</span><span> </span></span></span>− 10t + 20</span><span>
</span></span><span>
</span>
We're going to solve each of the systems to determine the solution.
<u>System
</u>

using a graph tool
the solution is the line 
see the attached figure N 
<u>System
</u>

using a graph tool
the solution is the shaded area
see the attached figure N 
<u>System
</u>

using a graph tool
The system has no solution
see the attached figure N 
<u>System
</u>

using a graph tool
the solution is the shaded area
see the attached figure N 
therefore
<u>the answer is</u>
<u>System
</u>

Answer:
in three hours he would have used up 3.75 gallons of gas. He would have 6.25 gallons of gas left in his tank after driving 3 hours.
Step-by-step e
Slope intercept form is y=mx+b.
Y and x stay.
M is your slope.
B is your y-intercept.
Hope that this helps!