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Answer: 
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Explanation:
The identity we'll use is cos(-x) = cos(x) for any value of x.
So cos(-150) = cos(150).
Then locate the angle 150 on the unit circle. The terminal point is 
The x coordinate of this terminal point is the value of cos(150).
Answer:
Morning's average rate = 50 mph, and Afternoon's average rate = 25 mph.
Step-by-step explanation:
Suppose he drove 150 miles for X hours, then his average rate in the morning was (150/X) mph.
Given that he spent 5 hours in driving.
And he drove 50 miles for (5-X) hours, then his average rate in the afternoon was 50/(5-X) mph.
Given that his average rate in the morning was twice his average rate in the afternoon.
(150/x) = 2 * 50/(5-x)
150/x = 100/(5-x)
Cross multiplying terms, we get:-
150*(5-x) = 100*x
750 - 150x = 100x
750 = 100x + 150x
750 = 250x
x = 750/250 = 3.
It means he spent 3 hours in the morning and 2 hours in the afternoon.
So morning's average rate = 150/3 = 50 mph.
and afternoon's average rate = 50/(5-3) = 25 mph.
I think it is 55 because 85-30 = 55
Hope this helps! :D
Answer:
x = 1 , 7
Step-by-step explanation:
Solution:-
- The given equation is as follows:
y = x^2 - 8x + 7
- We can solve the above equation by either making factors or by using Quadratic formula.
Factor Approach:
- Using the constant "7" at the end of the quadratic equation we will determine two integer multiples such that their additions/subtraction results in "-8".
- So the only factor of "7" are:
7 x 1 = 7
-7 x -1 = 7
- We see that addition/subtraction of first (7 , 1 ) does not results in "-8", However, the sum of ( -1 , -7 ) = -1 - 7 = -8. So the correct factors are ( -1 , -7 ). So we replace "-8x" with our factors "-1x" and "-7x":
x^2 -x -7x + 7 = 0
- Take common multiples out of pair of two terms:
x*(x-1) -7*(x-1) = 0
(x-7)*(x-1) = 0
- So we equate each term in bracket with "0" and evaluate the values of x:
(x-7) = 0 , x = 7
(x-1) = 0 , x = 1
- So the solution to the quadratic equation is:
x = 1 , 7
