V = u + at
2.8 = u + a*8.5
2.8 = u + 8.5a
s = ut + 0.5at^2
40 = u*8.5 + 0.5*a*8.5^2
40 = 8.5u + 36.125a
(2.8 = u + 8.5a) * 8.5
23.8 = 8.5u + 72.25a
Subtract those equations
16.2 = - 36.125a
a = 0.448
2.8 = u + (8.5*-0.448)
2.8 = u - 3.8
u = 6.6 m/s
Answer:
A
Step-by-step explanation:
In this problem, first u would have to keep the base of 3, then multiply the two powers together to get -28.
However, u can't leave a negative power in the numerator, so u bring the base and the power down into the denominator, change the sign of the power to make it positive, and put a 1 in the numerator.
Its an acute or an obtuse triangle