The answer will be D. Hope it help!
Question:
A solar lease customer built up an excess of 6,500 kilowatts hour (kwh) during the summer using his solar panels. when he turned his electric heat on, the excess be used up at 50 kilowatts hours per day
.
(a) If E represents the excess left and d represent the number of days. Write an equation for E in terms of d
(b) How much of excess will be left after one month (1 month = 30 days)
Answer:
a. 
b. 
Step-by-step explanation:
Given
Excess = 6500kwh
Rate = 50kwh/day
Solving (a): E in terms of d
The Excess left (E) in d days is calculated using:

The expression uses minus because there's a reduction in the excess kwh on a daily basis.
Substitute values for Excess, Rate and days


Solving (b); The value of E when d = 30.
Substitute 30 for d in 



<em>Hence, there are 5000kwh left after 30 days</em>
Answer:
x are -5/2 and 0 . Y are 0 and 2.
If tan theta is -1, we know immediately that theta is in either Quadrant II or Q IV. We need to focus on Q IV due to the restrictions on theta.
Because tan theta is -1, the ray representing theta makes a 45 degree angle with the horiz axis, and a 45 degree angle with the negative vert. axis. Thus the hypotenuse, by the Pythagorean Theorem, tells us that the hyp is sqrt(2).
Thus, the cosine of theta is adj / hyp, or +1 / sqrt(2), or [sqrt(2)]/2
The secant of theta is the reciprocal of that, and thus is
2 sqrt(2)
---------- * ------------ = sqrt(2) (answer)
sqrt(2) sqrt(2)