Answer:
C. 15
Step-by-step explanation:
<h2>
<em><u>∠ADC=∠ABC/2=30/2=15</u></em></h2>
I am going to explain this using the substitution method, considering it appears to be the best in this situation.
We know (from the bottom equation) that y can equal 3x+20. Using this knowledge, we substitute the y in the top equation for 3x+20. Now, we have an equation that looks like this:
3x+20=x^2+2x
Now we need to move x to one side and then do some radicals (square roots).
Subtract the 2x on the right (since it is smaller, negatives = NONONO), which will give you
x+20=x^2
Now, we take the square root of both sides to get
rad(x+20)=x
Now we have to simplify. 20 doesn't have a square root, but 4 goes into 20, and 4 has a square root of 2. This now becomes
2rad(x+5)
This doesn't simplify any further... we have a problem... no way to isolate x as far as my knowledge goes... Sorry, can't help you any further than that, but another person or your teacher might be able to. R.I.P...
Answer:
a) 17.5
b) 15.6
c) 13.3
d) 21.51
Step-by-step explanation:
The given function is equal to:
f(x)=kx^2
where

where y=23
Clearing k=0.00025
a) 
b)
c) The function is equal to:
f(x)=k(1+2x)

where y=20
k=0.0024

d) 
Answer:
x = 28°
Explanation:
|| means parallel lines.
<u>reason</u>:
Alternate interior angles, so has same angle measure.
It's the same as adding 2 fractions the product of 2 rational numbers is rational