Answer:

Step-by-step explanation:
Recall that the quadratic formula gives you the pattern to follow in order to find the solutions to a quadratic equation of the form: 
It tells us that we need to use the parameters
and
in the following formula in order to get the answers for the x-values that solve it:

so, in our case,
,
, and 
then, replacing these values in the formula, we obtain:

Which looks like the third expression you are listing (although it is a little hard to read)
Answer:
50 rpm clockwise
Step-by-step explanation:
100/50 × 50/200 × 200/150 × 150/200 = 0.5
In an odd number of gears, the first and last rotate inthe same direction.
100 rpm × 0.5 = 50 rpm
Answer: 50 rpm clockwise
Answer: (B) SinA = 4/5
Step-by-step explanation: Sine= O/H or opposite of hypotenuse so in regards to the triangle opposite is 28 and hypotenuse 35 or 28/35 which also equals 4/5