15x2+10x-9x+7
8x3+20x2+3x+12
11x4+4x2-6x2-16
Hope this helps !!
Answer:

Step-by-step explanation:
First: multiply both sides by 4. 4 times c is 4c and the other sides cancels out as you are doing the inverse operation of division
Then, you have 
Subtract both sides by a squared
DO NOT TAKE THE SQUARE ROOT! This is because it is a squared plus 3b so you have to do the inverse of addition
From that you get 
Finally, divide both sides by 3.
You get 
Answer:
Step-by-step explanation:
The negative in front of the parenthesis changes the signs of the numbers and variables inside the parenthesis. We can rewrite as
4 - x - 1 = 6 and
3 - x = 6 so
- x = 3 and
x = -3
Step-by-step explanation:

<em>θ</em> is given to be in the fourth quadrant (270° < <em>θ</em> < 360°) for which sin(<em>θ</em>) < 0 and cos(<em>θ</em>) > 0. This means
cos²(<em>θ</em>) + sin²(<em>θ</em>) = 1 ==> sin(<em>θ</em>) = -√[1 - cos²(<em>θ</em>)] = -3/5
Now recall the double angle identity for sine:
sin(2<em>θ</em>) = 2 sin(<em>θ</em>) cos(<em>θ</em>)
==> sin(2<em>θ</em>) = 2 (-3/5) (4/5) = -24/25