1. 2x^2-x-15=0
A = 2
B = -1
C = -15
2. 10^2-2x=0
A = 10
B = -2
C = 0
3. x^2–3x-40=0
A = 1
B = -3
C = -40
4. x^2+3x-2=0
A = 1
B = 3
C = -2
5. 4x^2-17x+8=0
A = 4
B = -17
C = 8
Remember the equations should look like Ax^2+Bx+C=0 (in this order!!)
Answer:

Step-by-step explanation:

If there are 8 marbles in a group , and 5 out of every 8 is red, than in six groups there would be 5, 10, 15, 20, 25, 30 red marbles.
This lists the group of 6 sets.
30 red marbles in 6 sets.
Answer: second option.
Step-by-step explanation:
You must apply 
Then, given the right triangle and the angle D, the opposite side and the hypotenuse of the triangle are the following:

Therefore, when you substitute values, you have:

Reduce the fraction, then you obtain:
