John blinks every 6 seconds, Jeremy every 4 seconds, so they both will blink next on a common factor of 6 and 4, or an LCD, that'd be 12 seconds later, so at 00:00:12.
Answer: β ≠ ±1
Step-by-step explanation: For a system of equations to have an unique solution, its determinant must be different from 0: det |A| ≠ 0. So,
det ![\left[\begin{array}{ccc}1&\beta&1-\beta\\2&2&0\\2-2\beta&4&0\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%26%5Cbeta%261-%5Cbeta%5C%5C2%262%260%5C%5C2-2%5Cbeta%264%260%5Cend%7Barray%7D%5Cright%5D)
≠ 0
Determinant of a 3x3 matrix is calculated by:
det ![\left[\begin{array}{ccc}1&\beta&1-\beta\\2&2&0\\2-2\beta&4&0\end{array}\right]\left[\begin{array}{ccc}1&\beta\\2&2\\2-2\beta&4\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%26%5Cbeta%261-%5Cbeta%5C%5C2%262%260%5C%5C2-2%5Cbeta%264%260%5Cend%7Barray%7D%5Cright%5D%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7D1%26%5Cbeta%5C%5C2%262%5C%5C2-2%5Cbeta%264%5Cend%7Barray%7D%5Cright%5D)
![8(1-\beta)-[2(2-2\beta)(1-\beta)]](https://tex.z-dn.net/?f=8%281-%5Cbeta%29-%5B2%282-2%5Cbeta%29%281-%5Cbeta%29%5D)
β ≠ ±1
For the system to have only one solution, β ≠ 1 or β ≠ -1.
Answer:
B.
Step-by-step explanation:
If you rearrange the equation in b, you get
y=5(x-3)+15
This means that your f(1) is equal to f(3), or 15, and for each additional month, it increases by 5, which is what the table shows.
The three missing lengths are the left hypotenuse, x, the middle altitude, y, and the right hypotenuse, z.
9/y = y/16
y^2 = 9 * 16
y^2 = 144
y = 12
9^2 + 12^2 = x^2
x^2 = 225
x = 15
12^2 + 16^2 = z^2
z^2 = 400
z = 20
From left to right, the sides measure 15, 12, and 20 units.
