55mph.
you can solve it using the equation distance=speed x time
your total distance is 714, and you have 2 trains, one traveling some speed, x, and one traveling x+8, both traveling for 7 hours.
your equation would look like this

and you can then solve for x, which would be 47. this is the speed of the slower train, but 47+8=55 with give you the speed of the faster train.
Answer:
There is no significant difference between the two averages at 5% level
Step-by-step explanation:
Given that a a college student is interested in testing whether business majors or liberal arts majors are better at trivia.
The student gives a trivia quiz to a random sample of 30 business school majors and finds the sample’s average test score is 86. He gives the same quiz to 30 randomly selected liberal arts majors and finds the sample’s average quiz score is 89
Thus he has done a hypothesis testing for comparison of two means of different subjects. n =30

Since which is better is not claimed we use two tailed test here
We find that p value
our alpha
Since p >alpha, we find that there is no significant difference between the averages of these two groups and null hypothesis is accepted
A quadratic equation is one in which the highest exponent of x is 2.

is quadratic; the highest exponent is 2.
x³-3x²+1=0 is NOT quadratic. The highest exponent of x is 3, not 2.
5x-7=0 is NOT quadratic. The highest exponent of x is 1, not 2.
x²+3x-5=0 is quadratic; the highest exponent of x is 2.
x-5=9x+7 is NOT quadratic. The highest exponent of x is 1, not 2.
x²-x=3x+7 is quadratic; the highest exponent of x is 2.
Answer:
I believe the answer is A
He is correct. If the second equation is multiplied by 2 and added to the first equation, the result is 0=3 , which means the system has no solution.