Let the three numbers be x, y and z. Then x+y+z=75.
z = 2x. y = x - 9.
Eliminate y and z by substitution: x + (x - 9) + (2x) = 75
Then 4x = 75 + 9, or 4x = 84. x = 21, y = 21 - 9 = 12, and z = 2(21) = 42.
Check: Do 21, 12 and 42 add up to 75?
Multiply out the "a times the squared coefficient" part on the left-hand side (remember, in this one a = 1 so that does nothing), and convert the right-hand side to squared form. (This is where you use that sign you kept track of earlier, putting that sign in the middle of the squared expression.)
y-4+(9)=(x+3)^2
Simplify - combine like terms.
y+5=(x+3)^2
Move the constant term from the right back to the left.
y=(x+3)^2 - 5
Write in vertex form y=(a(x-h)^2) + k. In other words, if the squared term is x+h write it as x-(-h). If the k term is negative, write it as + (-k).
y=(x-(-3))^2 + (-5)
Now the values for h and k are clear.I hope that this is the answer that you were looking for and it has helped you.
-- Driving at 30 mph for 20 minutes (1/3 hour), you cover 10 miles.
-- Walking at 3 mph for 10 minutes (1/6 hour), you cover 0.5 mile.
-- Average speed = (total distance covered) / (time to cover the distance)
= (10.5 miles) / ( 1/2 hour)
= 21 miles per hour.
Answer:
31/35 has to be added
Step-by-step explanation:
5/7 plus 7/5 equals 2 4/35.31 plus 4 equals 35,31 has to be added
