The pythagorean theorem says that a² + b² = c²
You're given the b and the c so substitute the values in: a² + 12² = 15²
a² + 144 = 225; subtract 144 from both sides
a² = 81; square root each side
a = 9, or choice C
the answer is x = 20/3 + 4/3y
how to: 3x - 4y - 8 = 12
3x = 12 + 4y + 8
3x = 20 + 4y
x = 20/3 + 4/3y
34,235345 = thirty four million two hundred thirty
five thousand three hundred forty five
7/7-1/7=6/7 is the rest of work
1/7 work takes 2days
6*1/7=6/7 work takes 6*2days=12days
30 men takes 12 days to finish the rest of work (6/7)
18 men takes 18*12/30= 7.2days
