Question 1160320
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In the additional 12-2 = 10 hours, the additional distance she rides is 98-18 = 80 miles.  So her speed is 80/10 = 8mph.<br>
The linear equation for the distance from her house is y = ax+b -- or, using m for miles and h for hours, m = ah+b.<br>
In that equation, a is the slope (her speed) and b is the y-intercept, which in this problem is her distance from her house when she starts riding.<br>
We have determined that her speed a is 8; to determine b we use either given data point.<br>
At 2 hours, she was 18 miles from her house:
{{{18 = 2(8)+b}}}
{{{b = 2}}}<br>
She started her ride 2 miles from her house.<br>
The linear equation for her distance from her house is<br>
{{{m = 8h+2}}}<br>