Answer:
x = 40
y = 62
Step-by-step explanation:
I figured out the answer by finding the x on the left triangle first by writing an equation:
(3x - 18) + (x + 7) + (x - 9) = 180
once I worked that I plugged in the number which was 40.
Then for the triangle to the right I also plugged in the numbers for x and got 118 degrees I took 180 and subtracted 118 to get my answer of 62 for y.
This comes from subtracting 4 from both sides.
For simplicity, dy/dx means f'(x);
We have y = ( 8 - x^2 ) / 2x;
Then, y = 4/x - x/2;
So, f'(x) = (4/x - x/2)' = (4/x)' - (x/2)' = -4/(x^2) -1/2 because we use <span> d<span>ifferentiation formulas, such as : (f+g)' = f' + g'; (cf)' = cf'; x'=1; (1/x)' = -1/(x^2);
</span></span>Finally, f'(4) = -4/16 -1/2 = -4/16 - 8/16 = -12/16 = -3/4.
The correct answer is E.
