Pythagorean theorem:
AC² + BC² = AB²
since this is isosceles (2 sides the same length), we can just let BC = AC and get
AC² + AC² = AB²
2AC² = AB²
AC² = AB²/2
AC = √(AB² / 2)

AC and BC are 6 meters
Answer:
there are no solutions as the two straight lines represented by the two equations are parallel, so they have no point in common
Step-by-step explanation:
general equation of a straight line: ax + by + c = 0
the slope (or raise) of a straight line m is equal to -a/b (b=1 a=-2 in this exercise as the equation is 1y=-2x - 4)
so m1 = -2/1 = -1/2
and m2 = -2/1 = -1/2
there is also a geometrical explanation, but I am not sure if it could be too complex
Roberto overtakes Juanita at the rate of (7.7 mi)/(11 h) = 0.7 mi/h. This is the difference in their speeds. The sum of their speeds is (7.7 mi)/1 h) = 7.7 mi/h.
Roberto walks at the rate (7.7 + 0.7)/2 = 4.2 mi/h.
Juanita walks at the rate 4.2 - 0.7 = 3.5 mi/h.
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In a "sum and diference" problem, one solution is half the total of the sum and difference. If we let R and J be the respective speeds of Roberto and Juanita, we have
R + J = total speed
R - J = difference speed
Adding these two equations, we have
2R = (total speed + difference speed)
R = (total speed + difference speed)2 . . . . . as computed above
Median as there is an outlier (anomaly)
is that what you looking for