Answer:
4 blue dogs
Step-by-step explanation:
Since there are 6 black dogs and 5 white dogs, there is 11 black and white dogs. There is 15 dogs in total, so you subtract 11 from 15, and that is 4. So, 4 dogs are blue.
Answer:
d=1
Step-by-step explanation:
Factor d^2 - 2d - 8 into (d-4)(d+2)
Move -2/d+2 onto the other side, changing it into 2/d+2.

Let the empty side equal zero.
Add 3/d-4 and 2/d+2

Then add that to -3d.

Multiply 0 by d+2 and d-4 to get 2d-2 by itself.
2d=2
d=1
I can't edit the equation, but it's d-4 althroughout the question. Sorry for being so slow.
<h3>
Answer: 1/2</h3>
The midsegment is always exactly half as long compared to the side it's parallel to.
Put another way, the longer side (4x+20) is twice long as the midsegment (3x).
2/3 of a right triangle is 60 degrees. Then x + (x+20) + 60 = 180 total.
2x + 80 = 180, so 2x = 100 and x = 50. The angles are 50, 70 and 60 (degrees)
What do you mean by "grades?"