3*40 + x / 4 = 45.
The answer of x comes out to be 60. Which means that the speed was travel around 60 miles per hour in the last one hour of the total journey.
Well to understand how i constructed its equation is very simple. I equated the total average speeds answer to 45 and just calculated the average speeds with the help of algebra where x is the number of miles..
54 degrees is the measure of its compliment since complentary angles add up to 90 degrees.
Use the quadratic formula, x=

(don't know how to type the "-"sign in the formula, so there is only the "+" in the formula)
in this case, a=1, c=34, b is unknown
from the roots, we can tell that -b+

=2(5+3i)=10+6i
Note: the original equation already give b as -b, so -(-b)=10, b=10
using b^2-4ac=(6I)^2,
b^2-4*34=-36
b^2=100
you will also get b=10
A. 80 students
B. 12 students
If you would like to solve y = x - 4 and 2 * x + y = 5, you can do this using the following steps:
y = x - 4
2 * x + y = 5
_____________
2 * x + (x - 4) = 5
2 * x + x = 5 + 4
3 * x = 9 /3
x = 9 / 3
x = 3
y = x - 4 = 3 - 4 = -1
The correct result would be x = 3 and y = -1.