Answer:
A design in which all levels of each independent variable are combined with all levels of the other independent variables. A factorial design allows investigation of the separate main effects and interactions of two or more independent variables.
Step-by-step explanation:
61*40=60*40+1*40=2400+40=2440.
Therefore [] is 4
I hope this helps .......
Answer:
It has two solutions
Step-by-step explanation:
The system 
If we try to simplify the fractions applying the Lesser Common Factor
We obtain this:

From this equation, you can see a square term coming up, from where we can say that this system has two solutions
Answer:
f(x)^-1 = 
Step-by-step explanation:
f(x) = (4x - 3) / 7
y = (4x - 3) / 7
x = (4y - 3) / 7
x / 7 = 4y - 3
x/7 + 3 = 4y
y = 