When you write URGENT the Brainly cops think you may be taking a test.
y = ax² + c thru (-1,4) and (0,8)
Substituting in the coordinates of each point for x and y gives two equations:
4 = a (-1)² + c
8 = a (0²) + c = c
From the second one we see c=8. Substituting into the first one,
4= a + 8
a = 4-8 = -4
Answer: a=-4, c=8
Check:
f(x) = -4x² + 8
f(0) = 8, good
f(-1) = -4(1) + 8 = 4, good
The answer (i think) is 3 <span>≥</span> x. hope i helped
<span>9, 12, 19, 30, ...
</span>formula for the nth term is;
<span>2n^2 + 3n - 10</span>
Answer:
x = 387
Step-by-step explanation:
The wind acts in the opposite direction to the plane when the time is longer.
The wind acts in the same direction as the plane when the time is shorter.
Equation
d = r*t
Givens
- d = 1720
- x = plane's speed
- y = wind speed
- t1 = 5 hours
- t2 = 4 hours.
Substitution
- d = (x + y) * t
- 1720 = (x + y) * 4
- 1720 = (x - y) * 5
Since the two distances are the same, you can equate the right hand sides.
- (x + y) * 4 = (x - y)*5 Remove the brackets.
- 4x + 4y = 5x - 5y Add 5y to both sides
- 4x + 4y + 5y = 5x - 5y + 5y Combine all the terms.
- 4x + 9y = 5x Subtract 4x from both sides
- 9y + 4x - 4x = 5x - 4x Combine
- 9y = x
Now use one of the given equations with the distance
- 1720 = (x + y)*4 Substitute 9y for x
- 1720 = (9y + y) * 4 Combine
- 1720 = 10y * 4 Multiply the right
- 1720 = 40y Divide by 40
- 1720/40 = 40y/40 Do the division
- 43 = y y = wind speek
- 9y = x x = 9*y
- 9*43 = x
- x = 387 miles per hour.
Answer:
c
Step-by-step explanation:
