Seeing as there are three coins, which means there are 3 heads and 3 tails.There's only a 50% chance it'll land on either side one one coin. I believe the chances to get two heads, and one tail would be somewhere around 80%, since there are only 8 possible outcomes.
The value of a2 will be I dont care
Y=-x+2
2y=x-8
these two lines both go through the point (4,-2)
solve: substitute the y in the second equation with (-x+2):
2(-x+2)=x-8
-2x+4=x-8
add 2x on both sides:
4=3x-8
add 8 on both sides: 12=3x
divide by 3 on both sides: x=4.
find y: y=-x+2=-4+2=-2
the solution is (4,-2)
two times as long as what? 2 times as long can be written as 2x.