The quadratic formula is
.
From the problem, a is 1, b is -1, and c is 12. Plugging in these values gives:

Because there is a square root of a negative number, there is no solution.
The percent of discount is 70%.
Answer:
m∠CDE = 35°
Step-by-step explanation:
The exterior angle CDE is equal to the sum of the opposite interior angles, BCD and DBC. So, you have ...
6x -13 = (2x+10) +(x +1)
3x -24 = 0 . . . . . . . . . . . . subtract the right side, simplify
x -8 = 0 . . . . . . . . . . . . . . divide by 3
x = 8 . . . . . . . . . . . . . . . . . add 8
6x -13 = 6·8 -13 = 35 . . . . substitute for x in the expression for CDE
The measure of angle CDE is 35°.
A triple number has 3 numbers and a double numbers has 2 numbers only.