Solve for x. 3(x+3) = -18 . A. x= -9 B.x= -7 c. x=-5 D. X=-3
1 answer:
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Answer:
The rate of current is 2.5 mph.
Step-by-step explanation:
The speed in the water when current is absent is 9 mph.
If the speed of the current is v mph then the upstream speed is (9 - v) mph and the downstream speed is (9 + v) mph.
Now, it takes 5 hours longer to travel 74 miles upstream than down stream, then we can write the equation as
⇒
⇒ 148v = 405 - 5v²
⇒ 5v² + 148v - 405 = 0
Applying Sridhar Acharya's formula we can write
(Neglecting the negative root)
⇒ mph (Rounded to the nearest 10th) (Answer)
Answer:
Step-by-step explanation:
given ,
equation y=ax²+bx+c
passing through points (1,6), (3, 20), and (−2,15).
then these points will satisfy the equation
at (1,6)
y = a x²+b x+c
6 = a(1)² + b (1) + c
a + b + c = 6------(1)
at (3 , 20)
y = a x²+b x+c
20 = a(3)² + b (3) + c
9 a + 3 b + c = 20------(2)
at (−2,15)
y = a x²+b x+c
15 = a(-2)² + b (-2) + c
4 a -2 b + c = 15------(3)
solving equation (1),(2) and (3)
a = 6 - b - c
9 (6 - b - c)+ 3 b + c = 20
6 b + 7 c = 34-------(4)
4 (6 - b - c) -2 b + c = 15
2 b + c = 3----------(5)
on solving equation (4) and (5)